(2-3x)^3-9x^2=0怎么算
问题描述：
(2-3x)^3-9x^2=0怎么算
RT.^3 = 三次方 ^2 = 二次方
答
(2-3x)^3-9x^2=0(2-3x)^3-1+1-9x^2=0(2-3x-1)[(2-3x)^2+(2-3x)+1]+(1+3x)(1-3x)=0(1-3x)(9x^2-15x+7)+(1+3x)(1-3x)=0(1-3x)(9x^2-15x+7+1+3x)=0(1-3x)(9x^2-12x+8)=0(1-3x)(9x^2-12x+4+4)=0(1-3x)[(3x-2)^2+4]=0[(3x...