因x²-5x-14=0
所以x²-5x=14
(x-1)×(2x-1)-(x+1)2+1
=2x²-x-2x+1-(x²+2x+1)+1
=2x²-3x+1-x²-2x-1+1
=x²-5x+1
=14+1=15