一元三次方程求解:3x^3+x^2=28

一元三次方程求解:3x^3+x^2=28

∵3x^3+x^2=28,∴3x^3-24+x^2-4=0,∴3(x^3-8)+(x^2-4)=0,∴3(x-2)(x^2+2x+4)+(x-2)(x+2)=0,∴(x-2)〔3(x^2+2x+4)+(x-2)〕=0,∴(x-2)(3x^2+7x+10)=0,∴x-2=0,或3…