Jawabanmu

2013-12-29T21:43:26+07:00
5x + 2y = -11 | -1 |  -5x - 2y = 11
-3x - y  = 7     | 2 | -6x -2y = 14  -
                           x      = -3

5x + 2y = -11
5(-3) + 2y = -11
2y = 4
y = 2

x = a
y = b

a + 3b = -3 + 3(2) = 3