Answer:
x = 10
Step-by-step explanation:
We can use the Angle Bisector of a triangle and proportions to solve this problem. Put the smaller triangle over the larger triangle.
AB x+4
------ = ----------
AC 2x+1
8 x+4
------ = ----------
12 2x+1
Using cross products
8(2x+1) = 12(x+4)
Distribute
16x+8 = 12x+48
Subtract 12x from each side
16x-12x +8 = 12x-12x+48
4x +8 = 48
Subtract 8 from each side
4x+8-8 = 48-8
4x = 40
Divide by 4
4x/4 =40/4
x = 10
