m+n=3,求2m的平方+4mn-2n的五次方-6

问题描述:

m+n=3,求2m的平方+4mn-2n的五次方-6

题目抄错了,应该是2n的2次方
2m^2+4mn+2n^2-6
=2*(m^2+2mn+n^2)-6
=2*(m+n)^2-6
=2*9-6
=12