Answer:
3a
Step-by-step explanation:
[tex] \huge \frac{9 {a}^{3}b }{3 {a}^{2}b } \\ \\ \huge = 3 {a}^{3 - 2} {b}^{1 - 1} \\ \\ \huge = 3 {a}^{1} {b}^{0} \\ \\ \huge = 3 {a} \times 1\\ \\ \huge \purple{= 3 {a} }[/tex]
