# Can you help me with a math problem?

Asked by jdogg (871) June 3rd, 2009

I need help with this proportional math problem.

12 2x+4
——=————-
x+1 7

(its supposed to be 12 over x+1 = 2x+4 over 7

Observing members: 0 Composing members: 0

No!

asmonet (21370)

I’m confused. That doesn’t exactly look like any math problem i’ve ever seen. Better drawing/example?

DeanV (14208)

DeanV (14208)

give me time i need to get paper and pencil and a bag of erasers…

cyn (6913)

asmonet (21370)

they are 2 fractions set equal to each other… 12 over x+1 = 2x+4 over 7

jdogg (871)

@asmonet: Ssh! You saw nothing!

DeanV (14208)

here solve it yourself….
84=(2x+4)(x+1)

cyn (6913)

<—I see all.

asmonet (21370)

Uhhh! Summoning…. Mental…. Math….. Powers!!!!!!!! Ahhhhhhhhhhhhh!!!!!!!!!!!

(death)

pikipupiba (1629)

Are we solving for x?
If so, then I got 2x^2+6x-80=0

If we’re not solving for x, then fuck it.

Allie (17506)

http://www.flickr.com/photos/nertperson/3594181086/

Complete with mistake, caught after photo taken. See note.

nikipedia (27727)

@dverhey :: wolframsbeta is the new hotness.

jrpowell (40514)

@johnpowell: Damn. So it is. But maybe not for math problems.

DeanV (14208)

its includes factoring and foiling so far ive gotten to 2x^2 + 6x – 80 =0
then i know you have to set up the next step like this (2x+or-?)(x+or-?) then you would get 2 answers
^2 means squared

jdogg (871)

keep on trucking! i cant find out the mulstiples of -80 to equal 6

jdogg (871)

Use the quadratic formula. I would solve it, but I’m too lazy.

I refuse to take the time to find the math symbols so I will sing it to you: x equals negative B plus or minus the square root of B squared minus 4AC all over 2A

Edit: Sung to the tune of Pop Goes The Weasel.

Allie (17506)

Don’t forget about the 2. This worked for me:

(2x – 10)(x+8)

If you put them back together you get:

2x^2 + 16x -10x -80

2x^2 + 6x -80

nikipedia (27727)

@nikipedia… or do that.

Allie (17506)

jdogg (871)

I used to think I liked math.

Allie (17506)

thank you thank you thank you!!!!!!!

jdogg (871)

x = 5 wtf

whatthefluther (13812)

X=5

DeanV (14208)

2×8 sq =128
6×8 = 48
128 + 48 does not equal 80

it would worrk if it was 2xsq – 6x

whatthefluther (13812)

Damn. You’re right. Disregard.

DeanV (14208)

I still lurve you kid…wtf

whatthefluther (13812)

Factor out 2 to get x^2 + 3x – 40 = 0. Then x = [- 3 +/- sqrt( 9 – ( -160) )] / 2.
9 + 160 = 169 = 13^2, so 2x = – 3 +/- 13; ie, x = 5 or x = -8.

ratboy (15157)

shouldnt you just cross multiply the fractions then when you get 84=2x^2+5 subtract five from five and 84 so you get 79 bring down the 2x^2 put it in a fraction so you do 79/2 = 2x^2 /2 . Then divide ? are you sure its not algebra looks it to me.

Harrow185 (298)

and i dont think you would use the quadratic formula unless the problem is 9+17x-18=0,then you would use the quadratic formula

Harrow185 (298)

Cross multiply.

Ivan (13479)

Yeah—no!

Strauss (22140)

@jdogg sorry about my last post. It was late, I was tired, I tried the math, and got frustrated.

Strauss (22140)

the answer is 5 and -8
84=(2x+4)(x+1)
84=2x^2+2x+4x+4….............84=2x^2+6x+4
(subtract 4)
80=2x^2+6x
(divide by 2)
40=x^2+3x…........0=x^2+3x-40…......(x+8)(x-5)...[F.O.I.L. to check the answer is correct] or plug in the numbers for (x)

cyn (6913)

x= ???
dont have any idea. and I’m studying this (again) in math! I can ask my teacher.

mbubbles (166)

or