The answer here is that x = 6 and y = 5. Here is how you can find this:
The thing to do here is to take the value that you have been given for x in the second equation and substitute it into the first equation. So then you have
3 (2y - 4) - 2y = 8
6y - 12 - 2y = 8
4y = 20
y = 5
Now you take this value of y and substitute it back in to the second equation to find x.
x = 2 (5) - 4
x = 10 - 4
x = 6
3x-2y=8...(1)
x=2y-4
Subtract 2y
==> x-2y=-4.....(1)
Subtract (1) from (2)
==> 2x=12 ==> x=6
To calculate y, we will use either equation (1) or (2)
x-2y=-4
Substitute with x=6
==> 6-2y=-4
Subtract 6 from both sides:
==> -2y=-10
Divide by -2:
==> y=5