21x^3+67x^2-36=0 solutins

Answer 1

tried: ±1, ±2, ±3
success at x = -3

by synthetic division
21x^3+67x^2-36=(x+3)(21x^2+ 4x - 12)
= (x+3)(3x-2)(7x+6)

so what do you think?