-------|-----------|-----------|-------- A B C Since point B is the midpoint of segment AC, the length of segment AC is two times the length of segment AB : 5x - 9 = 2*(2x). Simplify and solve for x 5x - 9 = 4x 5x - 4x = 9 x = 9 The length of segment AC is 5x-9 = 5*9 - 9 = 45 - 9 = 36. ANSWER