y²分之(x²-2xy+y²)除以xy分之(y²-xy)乘xy²,其中x=4,y=3.

问题描述:

y²分之(x²-2xy+y²)除以xy分之(y²-xy)乘xy²,其中x=4,y=3.

原式=(x-y)²/y²*xy/[-y(x-y)]*xy²
=-x(x-y)/y²*xy²
=-x²(x-y)
=-x³+x²y

(x²-2xy+y²)/y²÷(y²-xy)/xy *xy²
=(x-y)²/y²*xy/(y²-xy) *xy²
=(x-y)²*xy/y(y-x) *x
=(y-x)*x²
=(3-4)*4²
=-16