化简再求值:(x+2)(x-2)+(x-2)²+(x-4)(x-1)其中x²-3x=2
问题描述:
化简再求值:(x+2)(x-2)+(x-2)²+(x-4)(x-1)其中x²-3x=2
答
原式=x²-4+x²-4x+4+x²-5x+4
=3x²-9x+4
=3(x²-3x)+4
=3×2+4
=10