pretty simple algebra problem (i think)

• Aug 30th 2009, 10:23 AM
isuckatcalc
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?
• Aug 30th 2009, 10:29 AM
e^(i*pi)
Quote:

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!
• Aug 30th 2009, 10:45 AM
isuckatcalc
agh quadratic!! thank you very much. exactly what i needed.