xy的二次方-x的二次方y
=-xy(x-y)
=-6×5
=-30
(x+y)²
=x²+2xy+y²
=x²-2xy+y²+2xy
=(x-y)²+2xy
=25+12
=37我觉你可能误解算式了，若x-y=5，xy=6，求xy⑵-x⑵y与(x+y)⑵的值,求你帮助没有错呀xy²-x²y=xy(y-x)=-xy(x-y)