对于有理数a,b,定义a★b=2a+3b,则化简[(x+y)★(x-y)]★2x的结果为多少?
问题描述:
对于有理数a,b,定义a★b=2a+3b,则化简[(x+y)★(x-y)]★2x的结果为多少?
答
[(x+y)★(x-y)]★2x
=[2(x+y)+3(x-y)]★2x
=(2x+2y+3x-3y)★2x
=(5x-y)★2x
=2(5x-y)+3*2x
=10x-2y+6x
=16x-2y