Your roots would be 6, 4, and -2
First, let's find all the factors of 81:
81/3=27
27/3=9
9/3=3
3/1=1
So the factors of 81 are 3,3,3,3, (the numbers by which we divided here).
This means we can write down 81 as 3*3*3*3 or

- which is the answer to the question! (three to the power of 4)
A.)y=2/3x-7 is the answer
The answer to this is f(x) = (3/2)x - 2.