已知x²y+2xy²=2,求(x²y-2xy²)+(x²y+6xy²)的值

问题描述:

已知x²y+2xy²=2,求(x²y-2xy²)+(x²y+6xy²)的值

x²y=2-2xy²
(2-2xy²-2xy²)+(2-2xy²+6xy²)
=(2-4xy²)+(2+4xy²)
=4
ok啦,给分啊!