Math Help Please!

[P1nky]

took out old questions :)

edited on feb 19 09

could someone please factor this for me:

2x^2-7x+3

Thanks.
ill rep.

AND HERE ARE MORE:
http://answers.yahoo.com/question/index?qid=20090219202742AAwxbLm

[ZephyrsFury]

s<2 = s<4 //opposites are equal
x - 21 = 3x -5
x = 16
s<2 = 4(16) - 21
= 43 //size of angles 2 and 4 is 43 degrees

s<3 = s<1

360 = s<1 + s<3 + s<2 + s<4 //all angles must equal 360 degrees
= 2*s<1 + 2*s<2 //since opposites are equal
= 2s<1 + 2(43)
= 2s<1 + 86
2s<1 = 360 - 86
= 274
s<1 = 274/2
= 137 degrees //ANSWER


I'm pretty sure its correct. Narcle's working is also correct except 4*16 - 21 = 43 not 42 :p

[Narcle]

m<2 = M<4

4x-21=3x-5
x-21=-5
x=16

4*16-21=42

180-42=138
m<1=138

I think, so many people on this thread atm lol

[P1nky]

m<2 = M<4

4x-21=3x-5
x-21=-5
x=16

4*16-21=42

180-42=138
m<1=138

I think, so many people on this thread atm lol

OMG NARCLE I LOVE YOU!!!!!!
thanks oh yeah btw you made a mistake
4*16-21=43
not 42 :)

THANKS AGAIN REP++ too you ill post more problems here in a sec thanks!:duh: dum me

[Narcle]

OMG NARCLE I LOVE YOU!!!!!!
thanks oh yeah btw you made a mistake
4*16-21=43
not 42 :)

THANKS AGAIN REP++ too you ill post more problems here in a sec thanks!:duh: dum me

oops yeah spelling error ;)

[P1nky]

K I Posted Next Question Please Help On That Too !

REP++ TO ZEP THANKS! for other formula tho narcles shorter :) and easier thanks again

[foolishpaper]

Ok this is how you do the second question.

Since all sides are equal to each other you seperate the x and y:

First step we find out what x is:

2x-6 = 5x
2x-5x-6=0
2x-5x=6
-3x=6
x=-2 (Divide both sides by -3)

Second Step we find out what y is:

5y = 7y+7
5y-7y=7
-2y=7
y=-7/2 (Divide both sides by -2)

So the answer would be

x= -2, y= -7/2

*If you want to find the length of each side
just substitute the x with -2 and the y with -7/2*




Cheers!:)

[ZephyrsFury]

5x = 7y + 7 2x - 6 = 5y
x = (7y + 7)/5

Substitute into the other equation:
2(7y + 7)/5 - 6 = 5y
(14y + 14)/5 - 6 = 5y
(14y + 14)/5 = 5y + 6
14y + 14 = 25y + 30
11y = -16
y = -16/11
x = (7y + 7)/5
= (7(-16/11) + 7)/5
= -7/11


*Hint: use a graphics calculator and solve use the simultaneous solver. ;)

EDIT:

Since all sides are equal to each other you seperate the x and y:


Are they all equal?

[foolishpaper]

5x = 7y + 7 2x - 6 = 5y
x = (7y + 7)/5

Substitute into the other equation:
2(7y + 7)/5 - 6 = 5y
(14y + 14)/5 - 6 = 5y
(14y + 14)/5 = 5y + 6
14y + 14 = 25y + 30
11y = -16
y = -16/11
x = (7y + 7)/5
= (7(-16/11) + 7)/5
= -7/11


*Hint: use a graphics calculator and solve use the simultaneous solver. ;)

EDIT:


Are they all equal?

I think so because the square in each corner means all sides are equal. If they not equal then ur answer is the right one :p

[ZephyrsFury]

No it means its a right angle. But a rectangle has right angles in every corner yet it doesn't have to have equal sides.

[P1nky]

thanks foolish

you deserve srl junior ill rep you thansk alot

[foolishpaper]

No it means its a right angle. But a rectangle has right angles in every corner yet it doesn't have to have equal sides.

Oh! I see now. So yea Zephyrs' answer is the right one p1nky!

[lakerzz8]

I think so because the square in each corner means all sides are equal. If they not equal then ur answer is the right one :p

You're wrong!

The square in each corner means every angle is 90 degrees...which it is in a rectangle...

[P1nky]

i think you did it wrong
its

2x-6=5y

and

7y+7=5x

and i dont know how to solve that...

i still didnt get it seeing zephs explanation :S

[foolishpaper]

You're wrong!

The square in each corner means every angle is 90 degrees...which it is in a rectangle...

Yea like i said before my bad. Anyways, look at zephyrs' it is the right one. My answers are only right if the shape is a square and not a rectangle!

[Narcle]

I was getting -7/11 for X as well.
Does it fit into it?

[foolishpaper]

[QUOTE=ZephyrsFury;354539]
5x = 7y + 7 2x - 6 = 5y
x = (7y + 7)/5

Substitute into the other equation:
2(7y + 7)/5 - 6 = 5y
(14y + 14)/5 - 6 = 5y
(14y + 14)/5 = 5y + 6
14y + 14 = 25y + 30
11y = -16
y = -16/11
x = (7y + 7)/5
= (7(-16/11) + 7)/5
= -7/11


*Hint: use a graphics calculator and solve use the simultaneous solver. ;)

QUOTE]

Just look at how Zephyr did it. His answers are correct. P1nky, you can look at mine only if there is going to be square shaped questions on the test. Good Luck tomorrow!

[palmpilot71]

Lol I'm in Grade 7 but im justing learning this stuff.It suczors.If you need more help just PM me I'll be glad to help

[Brain]

Yeah, so on the bottom one, if you still dont understand Zephyrs's:
bottom side = top side
left side = right side
so then:

2x-6 = 5y
5x = 7y+7

So solve for one variable on both of the equations

(top) 2x = 5y-6 ------> x = (5y-6)/2
(bottom) x= (7y+7)/5

since you know that x = x because they are the same variable.....

(7y+7)/5 = (5y-6)/2

and now solve for y (in this case I would cross multiply)

5*(5y-6) = 2*(7y+7)

distribute the coefficients.....

25y-35 = 14y + 14 //////////OMG!!!!!!!! 5*6 doesn't equal 35!!!!:duh: :duh: :duh:
I hate myself.......... so I'll restart with the right equation..... at the bottom, so you can see my mistakes.....


25y-35 = 14y+14

solve for y

25y = 14y+14+35
25y-14y = 14+35
11y = 49

therefore:

(((((((((((((((((((((((((((((((y = 49/11)))))))))))))))))))))))))))))))))))))

now that you have y, stick it one of your other equations and get x

7y+7 = 5x

7(49/11)+7 = 5x

343/11 + 77/11 = 5x 77/11 = 7

420/11 = 5x divide by 5, and you're golden

420/55 = x (might wanna simplify)

(((((((((((((((((((((((((((((((x = 84/11)))))))))))))))))))))))



hope I'm right.........wouldn't look good if a kid in calc II failed geometry.....:p:rolleyes:

EDIT!!!!


25y-30 = 14y+14

solve for y

25y = 14y+14+30
25y-14y = 14+30
11y = 44

therefore:

(((((((((((((((((((((((((((((((y = 4)))))))))))))))))))))))))))))))))))))

now that you have y, stick it one of your other equations and get x

7y+7 = 5x

7(4)+7 = 5x

28 + 7 = 5x

35 = 5x divide by 5, and you're golden

7 = x

(((((((((((((((((((((((((((((((x = 7)))))))))))))))))))))))))))


sorry for the mistake...stupid me...stupid multiplication! :duh: :duh: :duh: :duh:

[P1nky]

OK GUYS i edited and added new questions i need help with


THANKS ILL REP I NEED IT BY 2NITE lol test 2mooro

thanks again

[P1nky]

cmon anyone?

[rockman]

1)
The first one is a right triangle. It is because when you plug the two smaller numbers into the Pythagorean Theorum(A^2 * B^2 = C^2) It gives you the third number

Now the second part is acute because the two smaller numbers squared and added together is 181. Then, 13 squared is 169. Since the square root of 181 is bigger than the square root of 169, the triangle is acute, because to be right, that third large side would have to be the square root of 181 long.

2) I am 90% sure the area is 90.

Ok. If you took the places where the lines come together on the side and drew from there to the center point, all the way around, they would all be equilateral triangles(equal side lengths). Knowing that, all we need is the height if that line drew in to the center on your picture, and we know the area of that 1 triangle. Multiply times 6 to get the whole thing.

-Illustration:
-------/|\
-----/--|-\
-A--/--|--\
---/----|---\ B
--/---D|----\
-/------|-----\
-___________
-------C

(Had to put in the hashes so it would post right)

Lines A, B, and C are all the same length, 6. So, we need to find the length of line D. Ok, so using the pythagorean theorum, A(Hypotenuse) squared is 36, minus half of C which is 3, so 9 when you square. 36 - 9 = 25. Square root is 5. That is the length of line D. So, to find the area of the triangle, take half of C (3) times the height D (5). You get 15 as the area of the triangle.

Now, there are 6 triangles in your polygon, so multiply times 6, and you get 90!

Hope I made sense with all that. Feel free to ask questions.


- 9th Grader

[P1nky]

REP++ thanks but the second 1 was kind of confuzing :S

ADDED ANOTHER QUESTION

[rockman]

Ok, can you give me any more of a specific are that you can't get?

You are basicly finding that length of the line drawn up to the center, in order to find the area of 1 section (triangle) with the pythagorean theorum.

Then you multiply by the number of sections (triangles) you have in your polygon(also the number of sides) to find the total area.

I gotta get to bed, but i'll be back tomorrow, I promise.

[P1nky]

alrite goodnight hopefully someelse can help for some other questions

thanks rockman i think i get the second not sure though :)

[rockman]

Alright, well pm me then if you have any other questions:D

ooo Number 3....

Ok, so to find the area of that rectangle, we need the length times height (Area = L * W in your book). You have the height, 5, so we need to find that bottom length, the length.

Using the pythagorean theorum, sort of backwards, we are going to use the diagonal measurement with the height, to find the bottom length.

A^2 * B^2 = C^2 - (Where C is the long side - 13, and A is the height - 5. Just remember that A and B are the shorter sides.

A^2 * B^2 = C^2 (BTW, ^2 = squared, can't figure out a better way to put it)

5^2 * B^2 = 13^2

25 * B^2 = 169 (Simplified)

B^2 = 169 / 25 (Divided both sides by 25. It cancelled on the left side, since there was a times 25)

B^2 = 6.76

B = 2.6 (Found square root of both sides)


Now, to find the area of that rectangle, we use the length that we just found (2.6), times the height that they gave us (5). The area of the rectangle is 13.


Simple stuff once you get the hang of it. I hope that was clear enough.

So, to find the area of a similar problem:

- Plug the two numbers that they gave you into the Pythagorean Theorum, where A and B are the shorter sides, and C is the long side (Diagonal).

- Simplify the equation and find the square root of both sides.

- Use the number that you got for the unknown variable in the equation, times the other short side. (If its a rectangle) If its not a rectangle, then use the equation for that polygon.

[P1nky]

Updated:
6/03/08!

added 3 semester exam questions which is tomorow gonna go sleep and come in the morning to see the answer!

please help me ! thanks btw ill rep!

[P1nky]

omgz no1 did it :S sh*tz

[Finta1]

aff just answered an already answered question without pinkly edditing.

damn you rockman

u gets mein angry interwebs face

>;[

[snaes]

#3 answer + explanation:
60 sq units - you divided the rectangel into 2 equal triangles. by using the pathagorean therom (a^2 + b^2 = c^2) you get 5^2 + x^2 = 13^2 from there you simplfy....25 + x^2 = 169 so now subtrct 25 on each side to get: x^2 = 144 takes sq root of 144 and u get the x val of 12. so now you know the side lengths 5 (given) and 12(just figured out). so multiply them and get 60 square units (inches meters or whatever)

[P1nky]

thanks snaes... but too late semeseter exam done and summer is here! wooot

[Rubix]

i looked and looked at... im in enriched algebra in 8th grade... i give up i looked at it for like 30 minutes

[P1nky]

hey there guys

4 months or so? well here still no new thread but school started and i forgot algebra 1 lol :( yes im dumb lol :P got all geometry still in me haha
well now taking algebra 2:
and posted new questions please help meeee by tonite
ill rep you :P

btw there like 7 questions out of 25 lol so those i dont get much's :P

thank you!!!


The Questions:


AUG 26 08

#1-----2(3/4x - 5/8)=7/4

#2-----4(1/3 - 3x/5)=8/60

#3-----x/5 + x/3= 10

#4-----x/2 + 7= 3x/4

#5-----x/4 + 3= x/8 - 1

#6-----6x/5 * 10/3 DIVIDE 4/7=14/3

#7-----4/5 DIVIDE 9/10 DIVIDE 8/3x= 1/3

[WithoutFear]

here is number 5 for you...did all this stuff 2 years ago and sadly have forgotten most of it.

1. x/4 + 3 = x/8 - 1
Simplify this to
2. x/4 + 4 = x/8
To get rid of the 8 multiply both sides by 8
3. 2x + 32 = x
Subract 32 from both sides
4. 2x = x - 32
Subract x from both sides
5. x = -32

If you input -32 into the original problem you get

(-32)/4 + 3 = (-32)/8 -1

both equal -5

Hoped I helped...I will edit if i figure out more

EDIT: Figured out 4...pretty simple here

1. x/2 + 7 = 3x/4
Get rid of the 4 by multiplying by 4 on each side
2. 2x + 28 = 3x
Get rid of 2x by subtracting by 2x on each side
3. x = 28

If you input 28 into the equation you get
(28)/2 + 7 = 3(28)/4

both equal 21

Lets try numero 3

1. x/5 + x/3 = 10
First you have to get common denominators, in this case it would be 15
2. 3x/15 + 5x/15 = 10
Now you add the two fractions together
3. 8x/15 = 10
To get rid of the 15 you multiply both sides by 15
4. 8x = 150
Divide 150 by 8
5. x = 18.75

If you input 18.75 for x you get

(18.75)/5 + (18.75)/3 = 10

This comes to 3.75 + 6.25 = 10 which is true

Hope i helped there Timer...come on your that good of a programmer and a total noob like me schools you in math;)...jk, hope you do well on your Tests!

[P1nky]

THankx broooo!

so it's -32 right?
and the -5 was to check the answer ?

am i correct?


AUG 26 08

#1-----2(3/4x - 5/8)=7/4

#2-----4(1/3 - 3x/5)=8/60

#3-----x/5 + x/3= 10

#4-----x/2 + 7= 3x/4

#5-----x/4 + 3= x/8 - 1 CHECKED OFF

#6-----6x/5 * 10/3 DIVIDE 4/7=14/3

#7-----4/5 DIVIDE 9/10 DIVIDE 8/3x= 1/3

[WithoutFear]

yessir, you are correct. Its a little trick i learned for Alg. tests....ALWAYS CHECK ANSWERS...it will save your neck on some difficult problems. Trust me, got a solid A in alg 1

[P1nky]

dannng k thanks hey you got any others like teh last 2 and some others :)?

[boberman]

ahh to be young again!



#1-----2(3/4x - 5/8)=7/4

#2-----4(1/3 - 3x/5)=8/60

#3-----x/5 + x/3= 10

#4-----x/2 + 7= 3x/4

#5-----x/4 + 3= x/8 - 1

#6-----6x/5 * 10/3 DIVIDE 4/7=14/3

#7-----4/5 DIVIDE 9/10 DIVIDE 8/3x= 1/3

#1
First take the 2 through to get
6/4x - 10/8 = 7/4
next simplify
3/2x - 5/4 = 7/4
next, multiply by 4.
12/2x - 20/4 = 7
simplify again
6/x - 5 = 7
add 5 to both sides
6/x = 2
times both sides by x
6 = 2x
and divide by 2
x = 3.

#2
again, take the 4 through first.
4/3 - 12x/5 = 8/60
Find a common denominator to combine the fractions. 15 will do so multiply by the difference to get
20/15 - 36x/15 = 8/60
put the fractions together to get
(20 - 36x)/15 = 8 / 60
multiply both sides by 15
20 - 36x = 8 / 4
simplify
20 - 36x = 2
subtract 20 and multiply by -1 to make things neat to get
36x = 18
divide by 36
x = 18 / 36
and simplify
x = 1/2

#3
first, find the common denominator. Looks like 15 again.
3x/15 + 5x/15 = 10.
simplify
8x/15 = 10
and multiply both sides by 15
8x = 150
and divide by 8 to get
x = 75/4

#4
first, move the x's to the same side by subtracting the x from the left to get
x/2 - 3x/4 + 7 = 0
combine the x's. first find a common denominator for them so it looks like
2x/4 - 3x/4 + 7 = 0 ->
-x/4 + 7 = 0
subtract the 7 over
-x/4 = -7
multiply by a negitive 4 to get
x = 28

#5
Again, get the x's to the same side
x/4 - x/8 + 3 = -1
and combine them..
2x/8 - x/8 + 3 = -1 ->
x/8 + 3 = -1
subtract the 3 over
x/8 = -4
and multiply both sides by 8 to get
x = -32

#6 (I hate these problems, but they are common)
First I would flip the 4/7 to the top to get (multiplication is much easier then division.)
6x/5 * 10/3 * 7/4 = 14/3
then simplify it
420x/60 = 14/3
and simplify it some more
7x = 14/3
divide both sides by 7 to get
x = 2/3

#7 4/5 DIVIDE 9/10 DIVIDE 8/3x= 1/3
Ok, the trick to this is going to be to flip it, simplify it, then flip it again :D so the first step
((4/5) / (9/10)) * 3x/8 = 1/3
then flip again
(4/5) * (10/9) * (3x/8)
then multiply through
120x/360 = 1/3
and simplify
x/3 = 1/3
Times both sides by 3 to get
x = 1

I was somewhat tired while doing this so check my work (It aint my homework) But I believe the answers for the most part should be correct. At very least the method to get them is.

If you go onto higher math (Calculus) this stuff will be like second nature to you. I sometimes slip a negative here and there. but I've pretty much gotten to the point where I can look at any algebra problem and instantly know what steps I want to take. Its like calculus gives you some sort of magic math algebra intuition (Scary I know)

[P1nky]

Guys i put up 2 questions please help me!!!
will post more!

[mixster]

TOOK OUT OLD QUESTIONS

NEW QUESTIONS(10/12/08):


1)At Used Book Sale, 5 paperback books cost $3.75. The total cost, c, of purchasing n paperback books can be found by-
a) subtracting n from c
b) dividing n by the cost of 1 book
c) Multiplying n by c
d) multiplying n by the cost of 1 book

2)Randy has $30 to spend at a town fair. the admission price is $6 and each ride costs $2. which inequality can be solved to find how many rides randy can afford?
NOTE: (> ARE ALL UNDERLINED, like _ and > on top of that underline!!!)
a) 30>6 + 2r
b) 30<6 + 2r
c) 30> 6r + 2
d) 30< 6r + 2


WILL RE-EDIT AND POST LIKE 5 MORE SOON!!
ILL REP YOU FOR SURE AND LOVE YOU

1) d
2) b

1) c := n * $3.75
c := 5 * 3.75
c := 18.75.

2) 30 := 6 + 2r where r = rides
24 := 2r
12 := r;
12 rides can be ridden.

[osmm]

1) d.
2) b.

Easy stuff, pre-algebra?

[MylesMadness]

yeah, its pre-algebra. I am just starting to take it.

[P1nky]

Added 4 more QUESTIONS!!!!

1-2 DONE!

3-6 please!!!!

and rep to both for helping on 1-2!!!

please need by tonight! thank you!

[pwnaz0r]

psedopost representing help on msn, solving everysingle problem (please no report for spam, I helped him, just not here on msn :), be a nice person)

[P1nky]

lyer, l0l jp thanks dude REP to you and derek

-.- derek post here...
l0l

[HyperSecret]

I got 3,4,5 done for him. #6 is one of those that I would need the book or an example problem to be able to solve. One of those types or equations I don't possess off the top of my head. Like the other 3, I use them constantly in every math class you go through...


3)
ERA = 9 * ER / IP
So this leads to plugging in numbers…
2.25 = 9 * ER / 212
Multiply by 212 to get rid of fractions - > 447 = 9 * ER
Divide by 9 to solve for ER (Earned Runs) -> 53 = ER


4)
Area of circle – > A = Pie * r^2
So Area of the circle is -> A = 3.14 * 2^2 - > A = 3.14 * 4 -> A = 12.56
So it wants what was shaven off, the excess.
The area of the whole piece is 4 * 4 (area of a square) so 16
16 – 12.56 = 3.44 – Answer ( A )


5 )
Pythagorean Theorem – A^2 + B^2 = C^2
A & B are sides/legs of the triangle, and C is the hypotenuse(the red line/the diagnol)
So C = Sqrt(50^2 + 94^2) – Answer ( D )


P.S. – anything that is ^ means and exponent. So x^2 means x squared…

[P1nky]

ADDED new 6 questions 10/16/08 please help me here guys i get everything else except these questions!!!!

please need by 2nite! please explain! not just the answer.

[Method]

I did the first three. Maybe I'll do the others later, but not right now.

m = -1/2
Plug in -1 for x and 5 for y to get your y-intercept, which is the last value you'll need to write it in slope-intercept form.
y - 5 = -1/2(x - (-1))
y - 5 = -1/2x - 1/2
y = -1/2x + 9/2

You need to find the slope first.
(5 - 3) / (-4 - 2) (rise / run or change in y / change in x)
m = 2 / -6 or -1/3
Then, same thing as the last problem - plug in a point.
y - 3 = -1/3(x - 2)
y - 3 = -1/3x + 2/3
y = -1/3x + 11/3

y-intercept of 6 means b = 6. Therefore, we know the equation will look something like y = mx + 6. Then, we can find the slope using the rise / run formula.
(6 - 0) / (-4 - 0)
m = 6 / -4 or -3 / 2
y = -3/2x + 6

This is actually #5.
Anyways, since the line y = -3 is horizontal, you'll need a vertical line to be perpendicular to it. That means x = something. The line that goes through (-4, -7) is the line x=-4.

[P1nky]

added new question, quite easy hopefully i just hate factoring lol.

Thanks ill rep

[Method]

Look in your book. I'm positive there's at least a section or some mention of factoring. Not to mention the entire internet is your resource.

The answer is (2x - 1)(x - 3) by the way.

[Baked0420]

Problem:
2x^2-7x+3

A*C = 6 so two numbers multiplies = 6 and adds to -7 (-6, -1):
2x^2-6x-1x+3

Then pull out greatest common factor (GCF)
2x(x-3)+-1(x-3) or 2x(x-3)-1(x-3)

2x multiplied by x-3 plus -1 or minus one multiplied by x-3. (btw, don't do plus negative one just do minus one for the answer, both are right but minus one looks way better).

and no need for rep, I don't care bout rep, but you can rep me if you really wanna, I just don't care one way or another.