I would isolate x in the first equation:
x = 3y + 1
For the second equation, you could just substitute the x inside:
3x - 5y = 11
3(3y +1) - 5y = 11
9y + 3 - 5y = 11
4y + 3 = 11
4y = 8
y = 2
Using the y = 2, we can find x.
x = 3y + 1
x = 3(2) + 1
x = 7
x = 7 and y = 2
