Q2 of 64 Page 49

Find the zeros and number of zeros of p(x) = x2 + 9x + 18. Show them on a graph.

Here, p(x) = x2 + 9x + 18


To find the zeros of p(x), let p(x) = 0.


∴ x2 + 9x + 18 = 0


∴ x2 + 6x + 3x + 18 = 0


∴ x(x + 6) + 3(x + 6) = 0


∴ (x + 6)(x + 3) = 0


∴ x = –6 or x = –3


Thus, the number of zeros of p(x) = 2.


To draw the graph of this polynomial, consider the following values of x and corresponding values of p(x):



On plotting the above points on a graph paper we obtain the following shape of the graph:



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