Answer
$k=53$
Work Step by Step
Step 1: $\frac{k-5}{4}+9=21$
Step 2: Subtract 9 from both sides: $\frac{k-5}{4}+9-9=21-9$.
Step 3: $\frac{k-5}{4}=12$
Step 4: Multiply both sides by 4: $\frac{k-5}{4}\times4=12\times4$.
Step 5: $k-5=48$
Step 6: Add 5 to both sides: $k-5+5=48+5$.
Step 7: $k=53$
