Answer:
BC = 49
Step-by-step explanation:
Since B is the midpoint, AB is half of AC & AB equals to BC
3x-31 = 2(x+6) >> distribute 2 (AB is doubled here since AB=BC)
3x-31 = 2x+12 >> add 31 to both sides
3x = 2x+43 >> subtract 2x from both sides to get x alone
x = 43
AB=BC so you can use AB's equation
BC = x + 6
BC = (43) + 6
BC = 49
