Question 37844
Okay from
4r^2 - 25s^2 / 2r^2 + 3rs - 20s^2
we factor top and bottom and see if anything cancels out (it usually does)
(2r + 5s)(2r - 5s) / (r + 4s)(2r - 5s)
what a surprise, the 2r - 5s cancels, leaving the answer
(2r + 5s) / (r + 4s)