求解答,(要过程,谢谢!)

2025-05-09 19:27:44
推荐回答(1个)
回答1:

(2x-3)²-(x+y)(x-y)-y²
=4x²-12x+9-(x²-y²)-y²
=4x²-12x+9-x²+y²-y²
=3x²-12x+9
=3(x²-4x)+9

根据己知条件得:x²-4x=1,代入得:

原式=3+9=12