如果x+y=5,xy=0,则x²y+xy²=?x²-xy+y²=?

问题描述:

如果x+y=5,xy=0,则x²y+xy²=?x²-xy+y²=?

x+y=5,xy=0,则
x²y+xy²
=xy ( x+y)
= 0 x 5
= 0
x²-xy+y²
= x²+2xy+y² -3xy
=(x+y ) ² -3xy
= 5x5 - 0
= 25