(3+2x)^3-36x^2≥60x+8x^3

Question

(3+2x)^3-36x^2≥60x+8x^3

Answer 1

(5x)^3-36x^2>=60x+8x^3
125x^3-36x^2>=60x=8x^3
125x^3-36x^2-60x-8x^3>=0
117x^3-36x^3-60>=0
3x(39x^2-12x-20)>=0
x(39x^2-12x-20)>=0

{x>=0
{39x^2-12x-20>=0

{x<=0<br>{39x^2-12x-20<=0<br>