Answer:
x=6
Step-by-step explanation:
Since the angles are the same , we can use the angle bisector theorem
3 x
------- = --------
x-4 4
Using cross products
3*4 = x(x-4)
Distriubte
12 = x^2 -4x
Subtract 12 from each side
12-12 = x^2 -4x-12
0 = x^2 -4x-12
Factor
0 = (x-6) (x+2)
Using the zero product property
x-6 = 0 x+2 =0
x=6 x=-2
But x cannot be negative since it is a length
x=6
