Answer:
BC = 107
Step-by-step explanation:
Point B is between A and C.
AB = 3x-1
BC = 9x+8
AC = 139
We need to find BC for which we need to find x first.
Finding 'x':
We know that AB + BC = AC
*putting the values of AB, BC and AC*
3x-1+9x+8 = 139
12x+7=139
12x=132
x=132/12
x=11
Now, BC = 9x+8 = 9(11) +8
BC = 99+8
BC = 107
