Step-by-step explanation:
[tex] - \frac{3}{4} (8n + 12) = 3(n - 3)[/tex]
[tex] - 3(8n + 12) = 12(n - 3)[/tex]
[tex] \cancel{- 3}(8n + 12) = \cancel{12}(n - 3)[/tex]
[tex] - (8n + 12) = 4(n - 3)[/tex]
[tex] - 8n - 12 = 4n - 12[/tex]
[tex] - 8n - 4n = - 12 + 12[/tex]
[tex] - 12n = 0[/tex]
[tex]n = 0[/tex]