x/5 + y/6=5

2x/5 + y/3=-2

use sub method

first one times 30 ---> 6x+5y=150

2nd times 15 ----> 6x + 5y = -30

If I subtract them, I get
0 = 180 which is nonsense

Your equations have no solution
(they represent two distinct parallel lines, thus they never meet)