如果(3x²-2)-(3x²-y)=2,那么代数式(x+y)+3(x-y)-4(x-y-2)的值为

问题描述:

如果(3x²-2)-(3x²-y)=2,那么代数式(x+y)+3(x-y)-4(x-y-2)的值为