Complete Quadratic Graph Tables

When plotting the graph of a quadratic equation, it's useful to draw out and complete a table so that we can find our coordinates to plot.

The x values are fixed and the corresponding y values are calculated.

 

Example:

Complete the following graph table:

 

 

 

Answer:

In the table above, the x values range from -3 to +3. 

 

To calculate our values for the y coordinates, we need to substitute the given values of x into the equation for the quadratic curve.

Likewise, if we are given the y coordinates we can substitute these values into the equation and solve.

 

Method

A = x² when x = -1

Therefore, A = -1² = 1

 

B = 1 - 2 = -1

 

C = 0 - 2 = -2

 

D = x² when x = 1 so D = 1² = 1

 

E = 4 - 2 = 2

 

F = -2 like the rest of that row

 

G = x² - 2 when x = 3 so G = 3² - 2 = 9 - 2 = 7

 

Let's consolidate this knowledge by working through some questions together.