-x^2y=2
-xy(x^5y^2-x^3y+2x)
=-xy(x*x^4y^2-x*x^2y+2x)
=-xy[x*(-x^2y)^2+x*(-x^2y)+2x]
=-xy(4x+2x+2x)
=-xy*8x
=8(-x^2y)
=8*2
=16