roots of a 3rd degree polynomial.

temp = -0.33362(x) + 0.0102(x^2) - 0.000136589(x^3) - 0.20819

-0.33362(x) + 0.0102(x^2) - 0.000136589(x^3) - (0.20819 -temp) = 0

temp is a known number and is between 34.7 and 38.7

This is equation that I need to solve in terms of x and x is between 0 and 25.

So which one of the 3 roots of this equation has the real root which is between 0 and 25?

Please help! This is for a program I'm writing for my summer research. This equation is the main component of the in the math so I really need this.

Many Thanks in advance.