Which expression is equivalent to21^3 sqrt15 - 9^3 sqrt 15 ? A.12
B.30^3 sqrt 15
C.12^3 sqrt 5
D.12^3 sqrt 15
I have tried to complete this And I get stuck like 15 mins into it.

Add or subtract polynomial : –12qr? +13rq?

Which expression gives the area of the triangle shown below

Aresearch group wants to find the opinions’ of city residents on the construction of a new downtown parking garage. what is the population of the survey downtown shoppers downtown visitors downtown workers city residents