Answer:
AB = 8
Explanation:
Using the similarity theorem of a triangle;
AC/AD = AB/AE
AC = AB + BC and AD = AE + ED
AB + BC/AE + ED = AB/AE
Substitute the given values
AB+12/15 = AB/6
Cross multiply
6(AB+12) = 15AB
6AB + 72 = 15AB
15AB - 6AB = 72
9AB = 72
AB = 72/9
AB = 8