Question

x^3-(2+a)x^2+x(a-11)-12a+12>0 怎么解? 过程.

Answer 1

x^3-(2+a)x^2+x(a-11)-12a+12

=x^3-2x^2-11x+12-ax^2+ax-12a

=x^3-x^2-x^2+x-12x+12-ax^2+ax-12a

=(x-1)(x^2-x-12)-a(x^2-x+12)

=(x-1)(x-4)(x+3)-a(x^2-x+12)

不知道如何了,抽时间看看