#### Answer

{$-\frac{19}{10}$}

#### Work Step by Step

Grouping like terms and then isolating the variable, we obtain:
Step 1: $-7-2n-6n=7n-5n+12$
Step 2: $-7-8n=2n+12$
Step 3: $-8n-2n=12+7$
Step 4: $-10n=19$
Step 5: $n=-\frac{19}{10}$
Therefore, the solution set is {$-\frac{19}{10}$}.