Posted by ladybug on Wednesday, June 6, 2012 at 10:46pm.
(-4)(-4)(x^2)(x^3)(y)(y^5)
16 x^5 y^6
recall that a^2-b^2 = (a-b)(a+b)
16x^2 - 25y^2 = (4x)^2 - (5y)^2 = (4x+5y)(4x-5y)
divide that by (4x+5y) and it cancels out, leaving the final answer:
4x-5y