o sketch a graph we need to find a set of points. This is most easily done by drawing up a table. The table for the graph given by the equation
3 
2 
1 
0 
1 
2 
3 

9 
4 
1 
0 
1 
4 
9 

3 
2 
1 
0 
1 
2 
3 

1 
1 
1 
1 
1 
1 
1 

13 
7 
3 
1 
1 
3 
7 
When filling in the table the most important thing to remember is that when you square a minus number you obtain a positive number, egnot 9.
DO NOT RELY ON YOUR CALCULATOR TO WORK OUT THE SQUARE OF A MINUS NUMBER.
Your calculator will tell you thatwhich is exactly wrong:is correct. The graph is shown below.