To solve this equation, you must multiply by a denominator and then subtract to isolate a variable.
Multiply by 4 on both sides of the equation.
[tex]\displaystyle 4(5 + \frac{k}{4}) = 4(3)[/tex]
[tex]\displaystyle 20 + k = 12[/tex]
Subtract 20 from both sides to isolate the k.
[tex]20 - 20 + k = 12 - 20[/tex]
[tex]\boxed{k = -8}[/tex]
The final answer is k = -8.