(x+1)的平方(2x-3)+(x+1)(2x-3)+x(x+1)(2x-3);
=(x+1)(2x-3)(x+1+1+x)
=(x+1)(2x-3)(2x+2)
=(1/2+1)(1/2x2-3)(1/2x2+2)
=3/2x-2x3
=-9