Answer:
n = 5
Step-by-step explanation:
By the property of intersecting chords within a circle.
[tex]18(n + 1) = 9(n + 7) \\ \\ \therefore \: 18n + 18 = 9n + 63 \\ \\ \therefore \: 18n - 9n = 63 - 18 \\ \therefore \: 9n = 45 \\ \therefore \: n = \frac{45}{9} \\ \huge \red{ \boxed{\therefore \: n = 5}}\\ [/tex]