Answer:
9a^2sqrt(ab)
Step-by-step explanation:
The first noticable thing is that 81 has a perfect square of 9.
So it is now 9sqrt(a^5b)
you can split the a^5, to a^4 × a.
you can now take the sqrt of a^4, which is a^2, and pull it out from the sqrt
You are now left with 9a^2sqrt(ab)
