You first have to make an simple equation.
= How many pennies
= How many quarters
After that, since a penny is 5 Cents and a quarter is 25 Cents, we make the equation as:
(cents)
To write the whole entire thing in an equation is:

Since I brought the x from the left to right, we change the positive "
" to negative "
"
To bring the '
' to
, we get rid of the "
"s from both equations.
Now, you are left with the simplified equation:








Now you find the
.
= 28

Conclude:
So the y was the quarter and the x was the pennies.
Quarters = 13
Pennies = 28