1. The Graphs of Quadratic Equations A quadratic equation is an equation that has a x 2 value. All of these are quadratics: y = x 2 y = x 2 + 2 y = x 2 + x – 4 y = x 2 + 2x – 3 Sunday, 20 December 2015 So quadratic means that there must be a x 2 in what ever y equals

2. If you were asked to draw the graph of y = x 2 + 2, follow these steps 1) Draw a chart putting in the x values from – 4 to +4 x-4-3-201234 The exam writer will probably do this for you

3. If you were asked to draw the graph of y = x 2 + 2, follow these steps 2) Calculate x 2 and put these values into the table. Notice that all of these are positive x-4-3-201234 x2x2 169410149 The values are always positive because a minus time a minus is a plus -3 X –3 = 9 etc.

4. If you were asked to draw the graph of y = x 2 + 2, follow these steps 3) Add the 2 onto the x 2 and put these values into the table. x-4-3-201234 x2x2 169410149 x 2 + 2181163236 18

5. If you were asked to draw the graph of y = x 2 + 2, follow these steps 4) You have done all that the equation asks so you will have the y value. x-4-3-201234 x2x2 169410149 x 2 + 2181163236 18 y 1163236 18 All you need to do now is to plot the x number against the y number.

6. x-4-3-201234 x2x2 169410149 x 2 + 2181163236 18 y 1163236 18

7. If you were asked to draw the graph of y = x 2 + x – 4, follow these steps 1) Draw a chart putting in the x values from – 4 to +4 x-4-3-201234 The exam writer will probably do this for you

8. If you were asked to draw the graph of y = x 2 +x – 4, follow these steps 2) Calculate x 2 and put these values into the table. Notice that all of these are positive x-4-3-201234 x2x2 169410149 The values are always positive because a minus time a minus is a plus -3 X –3 = 9 etc.

9. If you were asked to draw the graph of y = x 2 + x – 4, follow these steps 3) Add the x onto the x 2 and put these values into the table. x-4-3-201234 x2x2 169410149 x 2 +x12620026 20

10. If you were asked to draw the graph of y = x 2 + x – 4, follow these steps 3) Subtract 4 from these values to obtain x 2 + x – 4. x-4-3-201234 x2x2 169410149 x 2 +x12620026 20 x 2 + x – 482-2-4 -22816

11. If you were asked to draw the graph of y = x 2 + x – 4, follow these steps 3)You have done all the equation asks so you must have the y value. x-4-3-201234 x2x2 169410149 x 2 +x12620026 20 x 2 + x – 482-2-4 -22816 y82-2-4 -22816 All you need to do now is to plot the x number against the y number

12. x-4-3-201234 x2x2 169410149 x 2 +x12620026 20 x 2 + x – 482-2-4 -22816 y82-2-4 -22816