Answer
$a^{3} b$
Work Step by Step
We are given the expression $\frac{a^{12}b^{2}}{a^{9}b}$.
We can simplify this expression by using the quotient rule, which holds that $\frac{a^{m}}{a^{n}}=a^{m-n}$ (where a is a nonzero real number, and m and n are integers).
$\frac{a^{12}b^{2}}{a^{9}b}=(a^{12-9})\times (b^{2-1})=a^{3} b$