Solving Quadratic Inequalities

Example: Solve 3x² + 3x - 6 < 0

	Step 1: Go to and under Y1 enter 3x² + 3x - 6. Press . You are graphing a quadratic function, so the graph should be a parabola .
	Step 2: You want to de termine where the quadratic function is less than 0. So you need to look at the graph and determine what part of the graph lies be low the x -axis or the line y = 0.
	Step 3: The part of the graph that is below the x-axis is the part that lies between the x-intercepts. To find these x- intercepts or zero es , go to , the CALCULATE menu, and select 2: zero. Press . To find the intercept on the left, use the arrow keys to move the cursor to the left of the point, press . Then move the cursor to the right of the point, press , and then press again. The x-intercept is x= -2.
	To find the intercept on the right, go to , the CALCULATE menu, and select 2: zero. Press . Then repeat the process used above. The other intercept is x = 1.
	Step 4: Remember - since you are solving an inequality , the solution will be an interval or the union of two intervals. The solution to this inequality is the interval (-2, 1) or -2 < x < 1.
	Step 5: If you want to determine where a quadratic is greater than 0, you need to look at the graph and determine what part of the graph lies above the x-axis.