合并同类项3(x-y)的平方-7(x-y)+8(x-y)的平方+6(x-y)3(x-y)的平方-7(x-y)+8(x-y)的平方+6(x-y)急啊

问题描述:

合并同类项3(x-y)的平方-7(x-y)+8(x-y)的平方+6(x-y)
3(x-y)的平方-7(x-y)+8(x-y)的平方+6(x-y)急啊