Given equations are x-3y = 13 --------> (1)
5x+3y = 2 ---------> (2)
To eliminate the y value, add the equations (1)&(2).
x-3y = 13
5x+3y = 2
_________
6x = 15
Divide to each side by 6.
6x/6 =15/6
⇒ x = 5/2
Substitute the x value in (1).
5/2-3y = 13
-3y = 13-5/2
-3y = 21/2
Divide to each side by negitive 3.
-3y/-3 = 21/2*-3
⇒ y = -7/2