Did you get 2 and 3? The parabola crosses the xaxis at (2, 0) and also at (3, 0).
Let's think about those two numbers:
 The sum of 2 and 3 is 1.
 The product of 2 and 3 is 6.
2 and 3 are the roots of the quadratic equation. The roots satisfy the equation:
y = x^2 + x  6
y = (x  2)(x + 3)
y = x  2 or y = x + 3
If y is 0, then
0 = x  2 or 0 = x + 3
x = 2 or x = 3
CHECK:
0 = 2^2 + 2  6 or 0 = (3)^2 + (3)  6
0 = 4 + 2  6 or 0 = 9  3  6
0 = 6  6 or 0 = 9  9
0 = 0 or 0 = 0
 Here's another parabola to graph. Select 0 for a and 4 for b on the blue graph. In other words, click on the point (0, 4) on the blue graph. Now think about what two numbers have sum 0 and product 4? Can you name those two numbers by noting where the parabola crosses the x axis on the green graph?
 What is the quadratic equation?
 What is that equation in factored form?
 What are the roots of the equation?
 CHALLENGE: Can you find another parabola and identify the roots?
Final Task
Think about the following:
 How do a and b affect the location of the parabola?
 How can you know the quadratic equation by looking at the green graph?
Generalize how the applet can be used to find the roots of a quadratic equation.
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