To find AC
AC = AB + BC -------------------(1)
From the question
AB = 8
BC = 10x
AC = 17x + 1
substituting the values into eqn(1)
17x +1 =8 + 10x
collect like term
17x - 10x = 8 -1
7x = 7
divide both-side of the equation by 7
x = 1
But AC = 17x + 1
Hence AC = 17x + 1 = 17(1) + 1 = 17 + 1 = 18
Therefore, AC = 18
