Answer:
x = 4, BC = 17
Explanation:
AC = AB + BC , substitute values
7x - 3 = 2x + 3x + 5
7x - 3 = 5x + 5 ( subtract 5x from both sides )
2x - 3 = 5 ( add 3 to both sides )
2x = 8 ( divide both sides by 2 )
x = 4
Then
BC = 3x + 5 = 3(4) + 5 = 12 + 5 = 17