3x = -18 + 4y
16y = 58 + 5x
so
3x -4y = -18 ----> ×4
-5x+16y = 58
so the first sytem become 12x -16y = -72
Eliminate :
12x -16y = -72
-5x+16y = 58
------------------------ +
7x = -14
x = -2
so...
16y = 58 + 5x
16y = 58 -10
16y = 48
y = 48 /16
y = 3
So the solution is x = -2 and y = 3
Hopefully helpfull... ^_^