Question

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

Answer 1

[(x+y)*(x-y)]*2x

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

=(x+5y)*2x

=3(x+5y)-2*2x

=-x+15y