kak tolong ya dijawab pakai cara soalnya besok dikumpulin.

eliminasi x

2x -3y = 7 |×3
3x +2y = 4 |×2

6x -9y = 21
6x +4y = 8
_________-
-13y = 13
y = 13/-13
y = -1

subtitusi persamaan y
3x +2y = 4
3x + 2(-1) = 4
3x -2 = 4
3x = 4 + 2
3x = 6
x = 6/3
x = 2

x = a = 2
y = b = -1
nilai a - b
= 2 -(-1)
= 3 ➡ B

semoga membantu