Question

jreis & limitless. Im trying to figure out how to solve the equation.. x/(x=12)=3/(x=3)

Answer 1

(x+12)***

Answer 2

\[\frac{x}{x+12}=\frac{3}{x+3}\]?

Answer 3

satellite, yes.

Answer 4

alright so cross multiply those mofos.
you get x(x+3)=3(x+12)
then distribute each side,
x^2+3x=3x+36
now subtract 3x from each side,
x^2=36
now square root both sides,
x=-6 and 6

Answer 5

\[\frac{x}{x+12}=\frac{3}{x+3}\]
First, cancel the \(x+12\) and \(x+3\) by multiplying both sides by \((x+12)(x+3)\). This gives you:
\[(x+3)x=3(x+12)\]
Now you distribute the \(x\) and \(3\):
\[x^2+3x=3x+36\]
The \(3x\)'s cancel. So:
\[x^2=36\]
Take the squareroot of both sides:
\[x=\pm\sqrt{36}=\pm 6\]

Answer 6

^ what he said but less fancy

Answer 7

\(\pm 6\) just means "plus or minus 6", so 6 and -6.

Answer 8

K, but... cross multiply. like, what do you mean by that? and haha Jreis.lol

Answer 9

Cross multiply just means multiplying both sides (of the equation) by \((x+12)(x+3)\).

Answer 10

so its basically the denominators?

Answer 11

Yes. Precisely! :D

Answer 12

so itd be x times (x+12)(x+3)

Answer 13

Well, no. The \((x+12)\) goes away:
\[(x+12)(x+3)\frac{x}{x+12}=\frac{(x+12)(x+3)x}{x+12}=\frac{(x+12)}{x+12}(x+3)x=(x+3)x\]

\(\frac{x+12}{x+12}\) is just 1.

Answer 14

cross multiply means you take the denominator from left side and move it to the numerator of the right, and vice versa.
take the denominator from one side and bring to the other, so
(x+12) goes to right, (x+3) goes to left