Learning Resources

Investigation 3: Solving Polynomial Equations and Inequalities by Graphing

The x-intercepts are the points where the function value is equal to zero. If there is a sign change from positive to negative or from negative to positive, it will occur at an x-intercept. Test points can be used on either side of an x-intercept to determine the sign of the function in that region. Thus, the intervals over which the function is greater than or less than zero can be found.