Answer:
b = - 6
Step-by-step explanation:
Using the rules of exponents
[tex](a^{m}) ^{n}[/tex] ⇔ [tex]a^{mn}[/tex]
[tex]a^{-m}[/tex] = [tex]\frac{1}{a^{m} }[/tex]
Thus
[tex](y^{b}) ^{4}[/tex] = [tex]y^{4b}[/tex] = [tex]\frac{1}{y^{24} }[/tex] = [tex]y^{-24}[/tex], then equating the exponents
4b = - 24 ( divide both sides by 4 )
b = - 6
