The first equation can be multiplied by 5 and the second equation by 3.
3x - 3y = 3 | × 5
4x + 5y = 13 | × 3
15x - 15y = 15
12x + 15y = 39 +
________________
15x + 12x - 15y + 15y = 15 + 39
27x = 54
x = 54 : 27
x = 2
4·2 + 5y = 13
5y = 13 - 8
5y = 5
y = 5 ; 5
y = 1