化简求值:9(x-3)(x-2)-5(x-5)(2x-1)+3(x+1)(3x-4) 其中x=-1/2
问题描述:
化简求值:9(x-3)(x-2)-5(x-5)(2x-1)+3(x+1)(3x-4) 其中x=-1/2
化简求值:9(x-3)(x-2)-5(x-5)(2x-1)+3(x+1)(3x-4)
答
9(x-3)(x-2)-5(x-5)(2x-1)+3(x+1)(3x-4)
=9X^2-45X+54-10X^2+55X-25+9X^2-3X-12
=8X^2+7X+17
=8*(-1/2)^2+7*(-1/2)+17
=31/2=15.5