Answer
$x^4+4x^3-3x^2+16x-3$
Work Step by Step
Using the Distributive Property, the product of the given expression, $
(x^2+5x-1)(x^2-x+3)
,$ is
\begin{array}{l}\require{cancel}
x^2(x^2)+x^2(-x)+x^2(3)+5x(x^2)+5x(-x)+5x(3)-1(x^2)-1(-x)-1(3)
\\\\=
x^4-x^3+3x^2+5x^3-5x^2+15x-x^2+x-3
\\\\=
x^4+(-x^3+5x^3)+(3x^2-5x^2-x^2)+(15x+x)-3
\\\\=
x^4+4x^3-3x^2+16x-3
.\end{array}