Answer:
AD= 15
AB=30
Explanation:
We are given that the Point D bisect the line segment AB
Hence AD = DB
AD= 4x-1
BD=9x-21
Hence
4x-1=9x-21
adding 21 on both sides and subtracting 4x from both sides
4x-4x-1+21=9x-4x-21+21
-1+21=5x
5x=20
dividing both sides by x we get
x=4
Hence
AD = 4x-1
= 4(4)-1= 16-1=15
AD= 15
AB = 2 x AD
= 2 x 15
= 30