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jdogg's avatar

Can you help me with a math problem?

Asked by jdogg (871points) 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

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36 Answers

DeanV's avatar

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

But we still won’t help you…

DeanV's avatar

WolframAlpha is your friend.

cyn's avatar

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

asmonet's avatar

@dverhey: Stop helping him cheat! Bad Flutherite, bad!

jdogg's avatar

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

DeanV's avatar

@asmonet: Ssh! You saw nothing!

cyn's avatar

here solve it yourself….

asmonet's avatar


<—I see all.

pikipupiba's avatar

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


Allie's avatar

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

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

nikipedia's avatar

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

jrpowell's avatar

@dverhey :: wolframsbeta is the new hotness.

DeanV's avatar

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

jdogg's avatar

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's avatar

allie your right so far!!!!
keep on trucking! i cant find out the mulstiples of -80 to equal 6

Allie's avatar

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.

nikipedia's avatar


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

Allie's avatar

@nikipedia… or do that.

jdogg's avatar

nikipedia your amazing

Allie's avatar

I used to think I liked math.

El_Cadejo's avatar

@Allie hehe i automatically sung quadratic equation when i read it

jdogg's avatar

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

whatthefluther's avatar

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

it would worrk if it was 2xsq – 6x

DeanV's avatar

Damn. You’re right. Disregard.

whatthefluther's avatar

I still lurve you kid…wtf

ratboy's avatar

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.

Harrow185's avatar

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's avatar

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

Ivan's avatar

Cross multiply.

Strauss's avatar


Strauss's avatar

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

cyn's avatar

the answer is 5 and -8
(subtract 4)
(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)

mbubbles's avatar

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

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