Question

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

中间有一个特殊的符号，也帮忙告诉一下

Answer 1

由题意的
[(x+y)*(x-y)]*2π
=[2﹙x+y﹚-3﹙x-y﹚]*2π
=﹙5y-x﹚*2π
=2﹙5y-x﹚-3×2π
=10y-2x-6π

Answer 2

[(x+y)*(x-y)]*2π
=[2﹙x+y﹚-3﹙x-y﹚]*2π
=﹙5y-x﹚*2π
=2﹙5y-x﹚-3×2π
=10y-2x-6π