# Thread: pretty simple algebra problem (i think)

1. ## pretty simple algebra problem (i think)

I'm way beyond this but just starting the school year i'm having a complete brain block about how to do this.
how would i solve this equation?
5/x^2 = 8/(10+x)^2

i can expand the demoninator on the right, but then... i have no clue where to go. this is preventing me from solving a larger problem and it's driving me crazy that i don't know what to do. any advice?

2. Originally Posted by isuckatcalc
I'm way beyond this but just starting the school year i'm having a complete brain block about how to do this.
how would i solve this equation?
5/x^2 = 8/(10+x)^2

i can expand the demoninator on the right, but then... i have no clue where to go. this is preventing me from solving a larger problem and it's driving me crazy that i don't know what to do. any advice?
I'd cross multiply first to clear the fraction

$\displaystyle 5(10+x)^2 = 8x^2$

Expand the brackets, put into the form $\displaystyle ax^2 + bx + c = 0$ and solve the quadratic. Remember that the 5 is not squared!

3. agh quadratic!! thank you very much. exactly what i needed.