Answer:
3,3,3,3 ,-6, and -6.
Explanation:
Given the polynomial function
f(x) =

To find the roots of given polynomial we put f(x)=0
=0
Then we put
and
Now, we put each factor of (x-3 )equal to zero
x-3=0
x=3
x-3=0
x=3
x-3=0
x=3
x-3=0
x=3
Similarly , we put each factor of (x+6 ) equal to zero
Then we get
x+6=0
x=-6
x+6=0
x=-6
Multiplycity of 3=4
Multiplicity of -6= 2.
Multiplicity of any number is defined as the number of repeatation of that number in polynomial function.
Therefore, the roots of given polynomial function are 3,3,3,3-6 and -6.