Answer:
y - 8
Step-by-step explanation:
Since the fractions have a common denominator, subtract the numerators leaving the common denominator, that is
[tex]\frac{y^2-64}{y+8}[/tex] ← factor the numerator as a difference of squares
= [tex]\frac{(y-8)(y+8)}{y+8}[/tex] ← cancel the common factor (y + 8), leaving
= y - 8