I need help because all the answer choices my teacher put were wrong so I dont know what to do

Answer:
Equivalent Expression: [tex]\displaytext\mathsf{\frac{a^7}{b^8}}[/tex]
Step-by-step explanation:
Given the exponential expression, [tex]\displaystyle\mathsf{\frac{a^{12}\:b^{-3}}{a^{5}\:b^{5}}}[/tex]:
We could use the Quotient Rule of Exponents where it states that:
[tex]\displaystyle\mathsf{\frac{a^m}{a^n}\:=\:a^{(m\:-\:n)}}[/tex]
Since we have the variables, a and b as the base, we could simply apply the Quotient Rule and subtract their exponents.
[tex]\displaystyle\mathsf{\frac{a^{12}\:b^{-3}}{a^{5}\:b^{5}}\:=\:a^{(12\:-\:5)}\:b^{(-3\:-\:5)}}[/tex]
[tex]\displaytext\mathsf{=\:a^{7}\:b^{-8}}[/tex]
Next, we must transform the negative exponent of base, b, into positive by applying the Negative Exponent Rule, where it states that:
[tex]\large\text{$ a^{-n}\:=\:\frac{1}{a^{n}} $}[/tex]
Applying the Negative Exponent Rule will result in the following exponential expression:
[tex]\LARGE\text{$ a^{7}\:b^{-8}\:=\:[a^{7}\:\times\:\frac{1}{b^8}]\:=\:\frac{a^7}{b^8} $}[/tex]
Therefore, the equivalent expression is: [tex]\LARGE\text{$ \frac{a^7}{b^8} $}[/tex].