The length of AM is 21.
Given that,
Now
We can say that
AB = 2AM
And,
AM = [tex]\frac{AB}{2}[/tex]
AM [tex]=\frac{(8x-6)}{2}[/tex]
= 4x - 3
Now
3x + 3 = 4x - 3
4x - 3x = 3 + 3
x = 6
Finally,
AM = 3x + 3
= 3(6) + 3
= 18 + 3
= 21
Therefore we can conclude that The length of AM is 21.
Learn more about the geometry here: brainly.com/question/23533729