How to factor $42x – 14x^3$?

Question

Is the polynomial factored correctly? Would appreciate your help. This is for my son who is just learning to factor polynomials.

The polynomial to be factored is given below: $$42x – 14x^3$$

My attempt is: $$ –14x^3 + 42x = –14x(x^2–3) $$

Answer 1

You can also factor the $x^2-3$ term again into:

$$ (x^2 - 3) = (x + \sqrt{3})(x - \sqrt{3}) $$

Thus, your final version would be:

$$ 42x - 14x^3 = -14x(x + \sqrt{3})(x - \sqrt{3}) $$