Answer:
The length of AB is 40
Explanation:
The Midpoint of a Segment
If A and B are the endpoints of a segment, and C is the midpoint of AB, then the distance from A to C is equal to the distance from B to C.
We are given the lengths BC=3x-7 and AC=9x-61:
9x - 61 = 3x - 7
Subtracting 3x:
6x - 61 = - 7
Adding 61:
6x = 54
Dividing by 6:
x = 9
The total length AB is
BC+AC=3x - 7 + 9x - 61 = 12x - 68
Substituting x=9:
AB = 12*9 - 68 = 40
The length of AB is 40