tolong bantuin ya kakak2 yang jenius MTK :)

x= 4
y= 3

2x - 3y = a
2*4 - 3*3 = a
8 - 9 = a
a = -1

3x + y = -5a + b
3*4 + 3 = -5*-1 + b
12 + 3 = 5 + b
15 = 5 + b
15 - 5 = b
b = 10

a + b = -1 + 10
a + b = 9