a(x-t)+(b(y-x)=a(x-y)-b(x-y)=(x-y)(a-b)这是式子你打错了...应该是a(x-y)+(b(y-x)=a(x-y)-b(x-y)=(x-y)(a-b)你可以加Q420197028，我教你，这都是提取公因式
