Can i have help please

It’s 3a

as 9/3 = 3

a^3/a^2 = a

and the b’s cancel out

Its 3a because
you have to cancel the common factor which is b
means its now 9a^3/3a^2
factor 9 means 3 x 3a^3/3a^2
equals 3a^3/ a^2
a^3/ a^2 = a
3a

The answer should be 5.