Himpunan penyelesaian sistem persamaan linear dua variabel 2x+3y=13 dan -5x-2y=-38 adalah {(a-1,b+3)}.Nilai a+b adalah

2x + 3y = 13 |×2|
-5x -2y = -38 |×3|
4x + 6y = 26
-15x -6y = -114 +
-11x + 0 = -88
-11x = -88
x = 8

2x + 3y = 13
2(8) + 3y = 13
16 + 3y = 13
3y = -3
y = -1

x = a -1
8 = a -1
a = 9

y = b + 3
-1 = b + 3
b = -4

a + b = 9 + (-4)
a + b = 5