Solve this linear system by graphing

x-y=6

2x=12+2y

You need to isolate the variables. For the first equation add x to both sides, which leaves you with y.

For the second equation, divide each side by 2 leaving you with

x = 6+y. Subtract y from each side. Subtract x from both sides. Now you have y = x + 6.

Now graph those equations.