In order to solve the system of equations by graphing you must first define the variables
we have
[tex]y=35x[/tex]
where
x------> the number of sweatshirts
y-----> the income from selling
[tex]y=0.05(x-400)^{2} +9.492[/tex]
where
x------> the number of sweatshirts
y----->the cost to produce
Using a graphing tool
see the attached figure
therefore
the answer is
the solution of the system represent the number of sweatshirts for which cost and income are equal
