Answer
$$3(2x^2+8x+5)
$$
Work Step by Step
In order to do factoring when the first coefficient is not one, we must use some trial and error. After all, when considering the factor $(ax +b)(cx +d)$, a and c are no longer simply one. Thus, in addition to considering all of the factors of the constant term (the term that is not multiplied by a variable), we must consider the factors of the coefficient for the squared term. Using all of these factors, it is then just a matter of doing trial and error until one of the combinations of factors multiplies to get the correct answer, which must multiply out to get the original expression.
Here, we factor out the greatest common factors of all of the coefficients and constant terms:
$$3(2x^2+8x+5)
$$
