Answer:
[tex]\large\boxed{a.\ 23}[/tex]
Step-by-step explanation:
[tex]\dfrac{y-8}{5}=3\qquad\text{multiply both sides by 5}\\\\5\!\!\!\!\diagup^1\cdot\dfrac{y-8}{5\!\!\!\!\diagup_1}=5\cdot3\\\\y-8=15\qquad\text{add 8 to both sides}\\\\y-8+8=15+8\\\\y=23[/tex]