Question

(x+y)(x-y)-(2x+y)(x-y+1)计算要过程

Answer 1

(x+y)(x-y)-(2x+y)(x-y+1)

=x^2-y^2-(2x^2-2xy+2x+xy-y^2+y)

=x^2-y^2-2x^2+2xy-2x-xy+y^2-y

=-x^2+xy-2x-y

如果不懂,祝学习愉快!