Start with
[tex] \dfrac{5(n+4)}{3} = n-8 [/tex]
Multiply both sides by 3:
[tex] 5(n+4) = 3(n-8) [/tex]
Expand both sides:
[tex] 5n+20 = 3n-24 [/tex]
Subtract [tex] 3n [/tex] from both sides:
[tex] 2n+20 = -24 [/tex]
Subtract 20 from both sides:
[tex] 2n = -44 [/tex]
Divide both sides by 2:
[tex] n = -22 [/tex]