Hello!
The goal of elimination is to add or subtract the two equation to get rid of a variable
You can subtract these two equations to get rid of y
13x - x = 12x
-9y - -9y = 0
3 - -33 = 36
12x = 36
Divide both sides by 12
x = 3
Now you can put 3 in for x into one of the original equations
3 - 9y = -33
Subtract 3 from both sides
-9y = -36
Divide both sides by -9
y = 4
the answer is (3, 4)
Hope this helps!