对于有理数a,b,定义:a*b=3a-2b,若x,y均为有理数,试计算[(x+y)*(x-y)]*2x

问题描述:

对于有理数a,b,定义:a*b=3a-2b,若x,y均为有理数,试计算[(x+y)*(x-y)]*2x

[(x+y)*(x-y)]*2x
=[3(x+y)-2(x-y)]*2x
=(x+5y)*2x
=3(x+5y)-2*2x
=-x+15y