If B is the midpoint of segment AC, AB = x+7 , and AC = 5x−7 , then what is the length of BC?

2 answers

x=2
Make your sketch to see that BC = AC - AB
= 5x-7 - (x+7)
= 4x - 14
but AB = BC
x+7 = 4x - 14
21 = 3x
x = 7

BC = 4x-14 = 28-14 = 14