Q19 of 109 Page 3

If x = 1 is a zero of the polynomial f (x) = x3 – 2x2 + 4x + k, write the value of k.

Given,


f(x) = x3 – 2x2 + 4x + k


x = 1 is a zero,


So,


Keeping x = 1 we get,


f(1) = 13 – 2(1)2 + 4×1 + k


f(1) = 1 – 2 + 4 + k


f(1) = 5 – 2 + k


f(1) = 3 + k


– 3 = k


So we get,


k = – 3


More from this chapter

All 109 →
17

In Q. No. 15, write the sign of c.

 18

The graph of a polynomial/ (x) is as shown in Fig. 2.21. Write the number of real zeros of f (x).

 20

State division algorithm for polynomials.

 21

Give an example of polynomials f(x), g(x), q(x) and r(x) satisfying f(x) = g(x) .q(x)+ r(x), where degree r (x) = 0.