If you would like to know what is the product of (6 * x^3 + 3 * x) * (x^2 + 4), you can calculate this using the following steps:
(6 * x^3 + 3 * x) * (x^2 + 4) = 6 * x^3 * x^2 + 6 * 4 * x^3 + 3 * x * x^2 + 3 * 4 * x = 6 * x^5 + 24 * x^3 + 3 * x^3 + 12 * x = 6 * x^5 + 27 * x^3 + 12 * x
The correct result would be 6 * x^5 + 27 * x^3 + 12 * x.