Question

http://awesomescreenshot.com/0b32d76ffb

Answer 1

\[\frac{ (n-6)(n-4) }{ (n-6)(n-7) } - \frac{ 9 }{ n-7 }\]

Answer 2

\[\frac{ n-4 }{ n-7}-\frac{ 9 }{ n-7 }=\frac{ n-4-9 }{ n-7 }=\frac{ n-13 }{ n-7}\]

Answer 3

Thank you.