Answer:
see explanation
Step-by-step explanation:
Since B is at the midpoint of AC, then
BC = AB , substitute values
7x - 13 = 4x + 26 ( subtract 4x from both sides )
3x - 13 = 26 ( add 13 to both sides )
3x = 39 ( divide both sides by 3 )
x = 13
Thus
AB = 4x + 26 = 4(13) + 26 = 52 + 26 = 78
BC = 7x - 13 = 7(13) - 13 = 91 - 13 = 78
