Table-3.3
| x | -2 | -1 | 0 | 1 | 2 |
| y = x3 - 4x | 0 | 3 | 0 | -3 | 0 |
| (x,y) | (-2,-0) | (-1,3) | (0,0) | (1,-3) | (2,0) |
We see that the graph of y = x3 – 4x looks like the one given in the figure.
We see from the table above that –2, 0 and 2 are zeroes of the cubic polynomial x3 – 4x.–2, 0 and 2 are the x-coordinates of the points where the graph of y = x3– 4x intersects the X-axis. So this polynomial has three zeros. Let us take a few more examples. Consider the cubic polynomials x3and x3– x2 respectively. See Table 3.4 and 3.5
Table-3.4
| x | -2 | -1 | 0 | 1 | 2 |
| y = x3 | -8 | -1 | 0 | 1 | 8 |
| (x,y) | (-2,-8) | (-1,1) | (0,0) | (1,1) | (2,8) |