no.19 makasih banyakkk

2x - y = 1
-3x + 5y = 2

6x - 3y = 3
-6x + 10y = 4
---------------------+
7y = 7
y =1

2x - y = 1
2x - 7 = 1
2x = 8
x = 4

x + y = 4 + 1 = 5

semoga membantu! ^^