Answer
$(x-3)(5x+1)$
Work Step by Step
The two numbers whose product is $ac=
5(-3)=-15
$ and whose sum is $b=
-14
$ are $\{
-15,1
\}$. Using these two numbers to decompose the middle term, then the factored form of the expression, $
5x^2-14x-3
$, is
\begin{array}{l}\require{cancel}
5x^2-15x+x-3
\\\\=
(5x^2-15x)+(x-3)
\\\\=
5x(x-3)+(x-3)
\\\\=
(x-3)(5x+1)
.\end{array}
