已知x+y=a,试求(x+y)3(2x+2y)3(3x+3y)3的值.
问题描述:
已知x+y=a,试求(x+y)3(2x+2y)3(3x+3y)3的值.
答
(x+y)3(2x+2y)3(3x+3y)3,
=(x+y)3[2(x+y)]3[3(x+y)]3,
=(x+y)3•8(x+y)3•27(x+y)3,
=216(x+y)9,
=216a9.