Respuesta :

Step-by-step explanation:

solution

let,

AB = 9

AC = 9 + 3a - 6

AD = 12

AE = 12 + 20

now

AB/AD = AC/AE

or, 9/12 = 3 + 3a / 22

by cross multiply

or, 9×22 = 12×(3 + 3a)

or, 198 = 36 + 36a

or, (198 - 36)/36 = a

or, 4.5 = a