Answer:
AB = 9
AC = AB + BC
AB = 2x - 3
BC = 5x + 9
AC = 48
AC = (2x - 3) + (5x + 9)
2x - 3 + 5x + 9 = 48
2x + 5x = 48 + 3 - 9
7x = 42
x = 42 : 7
x = 6
AB = 2 · 6 - 3
AB = 12 - 3
