(x-y)(x-2y)-(3x-2y)(x-3y)
问题描述:
(x-y)(x-2y)-(3x-2y)(x-3y)
答案应为-2x-x*x-3x,
答
原式=x²-2xy-xy+2y²-(3x²-9xy-2xy+6y²)=x²-3xy+2y²-(3x²-11xy+6y²)=x²-3xy+2y²-3x²+11xy-6y²=-2x²+8xy-4y²