McGraw Hill Integrated II, 2012
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McGraw Hill Integrated II, 2012 View details
5. Quadratic Inequalities
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Exercise 14 Page 211

Since we have a strict inequality, the parabola will be a dashed line.

Practice makes perfect

To graph the quadratic inequality, we will follow three steps.

  1. Graph the related quadratic function.
  2. Test a point not on the parabola.
  3. Shade accordingly. If the point satisfies the inequality, we shade the region that contains the point. If not, we shade the opposite region.

Step 1

Let's draw the graph of the related function, which is y=x^2-2x-8.

Step 2

Next, let's determine which region to shade by testing a point. For simplicity, we will use (0,0) as our test point. Let's see if it satisfies the given inequality.
x^2-2x-8 < y
( 0)^2-2 ( 0)-8 ? < 0
0-2(0)-8? < 0
0-0-8 ? < 0
-8 < 0 âś“

Step 3

Since (0,0) produced a true statement, we will shade the region that contains the point. Also, note that we have a strict inequality. Therefore, the parabola will be dashed.