计算9-12（x-y）+4（x+y)^2 81(a-b)^2-4(a+v)^2 -2x^3+8x^2-8x_数学解答

计算9-12（x-y）+4（x+y)^2 81(a-b)^2-4(a+v)^2 -2x^3+8x^2-8x

人气：145 ℃　时间：2020-05-11 06:04:51

解答

(1) 4x^3+8x^2-15x-9
= 4x^3+2x^2+6x^2-15x-9
= 2x^2(2x+1)+3(2x^2-5x-3)
= 2x^2(2x+1)+3(x-3)(2x+1)
= (2x^2+3x-9)(2x+1)
= (2x-3)(x+3)(2x+1)