B is the midpoint of AC.
If BC is 3x - 7 and AC is 9x - 61, what is the length of AB?

The length of AB is 40

Step-by-step 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

42.4

step-by-step explanation:

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