B is the midpoint of AC. AB=7x-4 and BC=4x+5. Find AC.
A) 51
B) 68
C) 17
D) 34

Answer:
D) 34
Step-by-step explanation:
Since B is the midpoint, AB = BC
Plug the two in:
7x - 4 = 4x + 5
Solve for x:
3x = 9, x = 3
Find AB + BC
since BC = AB
AC = 4x + 5 + 4x + 5
AC = 8x + 10
AC = 8(3) + 10
AC = 24 + 10
AC = 34