(2x-1)²-(x-1)(x+2)
=(4x²-4x+1)-(x²+x-2)
=4x²-4x+1-x²-x+2
=3x²-5x+3
=2+3
=5

明白请采纳,有疑问请追问!
有新问题请求助,谢谢!