x²-5x=3
(x-1)(2x-1)-(X+1)^2+1
=2x²-3x+1-x²-2x-1+1
=x²-5x+1
=3+1
=4不懂的欢迎追问,如有帮助请采纳,谢谢!
(x-1)(2x-1)-(x+1)^2+1
=2x^2-3x+1-(x^2+2x+1)+1
=2x^2-3x+1-x^2-2x-1+1
=2x^2-x^2-3x-2x+1
=x^2-5x+1
=3+1
=4
(x-1)(2x-1)-(x+1)^2+1=x^2-5x+1,将 x^2-5x=3代入
(x-1)(2x-1)-(x+1)^2+1=4