Answer:
B. x = 7; AB = 9, AC = 12
Explanation:
12/4 = (x + 2)/(x - 4) (similar triangles theorem)
3 = (x + 2)/(x - 4)
Cross multiply
3(x - 4) = (x + 2)
3x - 12 = x + 2
Collect like terms
3x - x = 12 + 2
2x = 14
x = 14/2
x = 7
✔️AB = x + 2 = 7 + 2
AB = 9
✔️AC = (x + 2) + (x - 4) = (7 + 2) + (7 - 4)
AC = 9 + 3
AC = 12