已知xy=5,x-y=2,则代数式1/2x³-x²y²+1/2xy³的值为________
问题描述:
已知xy=5,x-y=2,则代数式1/2x³-x²y²+1/2xy³的值为________
答
1/2xy(x²-2xy+y²)=1/2xy(x-y)²=10
已知xy=5,x-y=2,则代数式1/2x³-x²y²+1/2xy³的值为________
1/2xy(x²-2xy+y²)=1/2xy(x-y)²=10