(2x+1)(x-1)-(x-3)的平方-x(2x-3),其中x平方-8x-5=0,化简后再求值.

问题描述:

(2x+1)(x-1)-(x-3)的平方-x(2x-3),其中x平方-8x-5=0,化简后再求值.

(2x+1)(x-1)-(x-3)²-x(2x-3)
=2x²-x-1-(x²-6x+9)-2x²+3x
=-x²+8x-10
=-(x²-8x)-10
=-15