3x^3 + 2x^2 = 4x
3x^3 + 2x^2 - 4x = 0
x(3x^2 + 2x - 4) = 0
x = 0 or 3x^2 + 2x - 4 = 0
x = 0 or (3x^2 + 2x) - 4 = 0
x = 0 or 3(x^2 + (2/3)x) - 4 = 0
x = 0 or 3(x + (1/3))^2 - 1/3 - 4 = 0
x = 0 or 3(x + (1/3))^2 - (13/3) = 0
x = 0 or 3(x + (1/3))^2 = 13 / 3
x = 0 or (x + (1/3))^2 = 13 / 9
x = 0 or x + 1/3 = sqrt(13/9) or x + 1/3 = -sqrt(13/9)
x = 0 or x = -1/3 + sqrt(13/9) or x = -1/3 - sqrt(13/9)