Step-by-step explanation:
[tex]slope \: = \frac{n - ( - 9)}{ - 6 - ( - 8)} \\ \\ \therefore \: 4 \: = \frac{n + 9}{ - 6 + 8} \\ \\ \therefore \: 4 \: = \frac{n + 9}{ 2} \\ \\ \therefore \: 4 \times 2= n + 9 \\ \\ \therefore 8= n + 9 \\ \\ \therefore \: n = 8 - 9 \\ \\ \huge \red{ \boxed{\therefore \: n = - 1}}[/tex]