先化简,再求值(x+1)^2(2x-3)+(x+1)(2x-3)+x(x+1)(3-2x),其中x=1/2RT

问题描述:

先化简,再求值(x+1)^2(2x-3)+(x+1)(2x-3)+x(x+1)(3-2x),其中x=1/2
RT

(x+1)^2(2x-3)+(x+1)(2x-3)+x(x+1)(3-2x)
=(2x-3)*[(x+1)^2+(x+1)]+x(x+1)(3-2x)
=(2x-3)*(x+1)*(x+2)-(2x-3)*(x+1)x
=(2x-3)*(x+1)*2
=-2*1.5*2
=-6

(x+1)^2(2x-3)+(x+1)(2x-3)+x(x+1)(3-2x)
=(x+1)^2(2x-3)+(x+1)(2x-3)-x(x+1)(2x-3)
=(2x-3)(x+1)[(x+1)+1-x]
=2(2x-3)(x+1)
=2(2*1/2-3)(1/2+1)
=2*(-2)*3/2
=-3/2