Polynomial Equations/Factor theorem! Please help!
Based on research, the
marketing team at Best of U predicts that when
the price of a bottle of a new SPF 50 sunscreen
is x dollars, the number, D, in hundreds, of
bottles sold per month can be modelled by the
function D(x)=-x^3+8x^2=9x+100

c) Determine the value(s) of x that will result
in sales of 17 200 bottles of sunscreen per
month. Interpret this answer.

Question

Polynomial Equations/Factor theorem! Please help! 
Based on research, the 
marketing team at Best of U predicts that when
the price of a bottle of a new SPF 50 sunscreen 
is x dollars, the number, D, in hundreds, of 
bottles sold per month can be modelled by the 
function D(x)=-x^3+8x^2=9x+100

c) Determine the value(s) of x that will result 
in sales of 17 200 bottles of sunscreen per 
month. Interpret this answer.