You have two equations and two unknowns. Start with the first equation: 2x+y=4. Solve for y.

2x+y=4

y=4-2x

Now take this and plug in "4-2x" for "y" in the second equation.

3x-y=6

3x-(4-2x)=6

3x-4+2x=6

5x-4=6

5x=10

x=2

Now that we have found x, plug "2" in for "x" in either the first or second equation to find y.

2x+y=4

2(2)+y=4

4+y=4

y=0

So the final answer is x=0, y=2. If you plug in these numbers to both equations you can verify they are correct.