Answer :
It is asking for the intercept.
y = x + 3 becomes y - x = 3
multiply it by two, so it becomes -2x + 2y = 6. Then add it to the other equation, and solve for y.
2x + 4y = 60
(2x + 4y) + (-2x + 2y) = 60 +6
6y = 66
y = 11
Plug in the known y into the the easiest equation.
11 = x +3
x = 8
Intercept: (8, 11)