解析:
由定义知:
(x+y)*(x-y)=3(x+y)-2(x-y)=3x+3y-2x+2y=x+5y
则:【(x+y)*(x-y)】*2 x
=(x+5y)*2x
=3(x+5y)-2(2x)
=3x+15y-4x
=-x+15y