Answer :

The length of BC is equivalent to 12 units

Midpoint of a line

If the midpoint if Ac is B, then the expressions below are true;

AB+BC = AC

AB = BC

Given the following parameters

AB = x + 6, and

AC = 5x - 6

BC = x + 6

Substitute

x+6+x+6 = 5x - 6

2x+12 = 5x - 6

2x-5x = -6-12

-3x = -18

x = 6

Determine the measure of BC

BC = x + 6

BC= 6 + 6

BC = 12units

Hence the length of BC is equivalent to 12 units

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