-a + b = -4 --- (1)
2a - 3b = -2 --- (2)
Adding twice of (1) to (2), we have:
2(-a + b) + (2a - 3b) = 2(-4) + (-2)
-2a + 2b + 2a - 3b = -8 - 2
-2a + 2a + 2b - 3b = -10
-b = -10
b = 10
Adding thrice of (1) to (2), we have:
3(-a + b) + (2a - 3b) + 3(-4) + (-2)
-3a + 3b + 2a - 3b = -12 - 2
-3a + 2a + 3b - 3b = -14
-a = -14
a = 14
Hence, a = 14 and b = 10.