Expert: Richard J. Raridon - 12/12/2010

Question
10th Grade, Age 15
Why do we set polynomial functions to zero when finding the zeros?  
In addition, when using a graphing calculator to find zeros, do you use the first x you find on the calculator and incorporate it into the equation to find the others?

Answer
It's not an equation unless you have an equals sign. Usually it's set up like f(x) = x^2+3x+4.  Then you try to find values for x that will make f(x) = 0.  Since I have never used a graphing calculator, I can't answer your question.  However, when working with a polynomial and you find that one solution is x=2, then dividing the polynomial by (x-2) makes the rest of it easier to solve.