One trick for this problem is to keep the 200 in the equation as if it was a variable whenever possible (like x or y) until the last few lines... This saves evaluating out the 200 quite a number of times.

First I start by diving by 25.. and turn it into:

1/12 = 8/(200 + w) + 8/(200-w)

At this point don't evaluate the 200 with anything till you get..

200(200-12*16) = w^2
200(200-192) = w^2
200(8) = w^2
1600 = w^2

Last edited by bluemagic; 01/21/14 04:11 PM.