Verify whether the indicated numbers are zeros of the polynomials corresponding to them in the following cases:

(i) f(x) = 3x+1; x =


(ii) f(x) = x2-1; x = 1, -1


(iii) g(x) = 3x2-2; x = , -


(iv) p(x) = x3-6x2+11x-6, x = 1,2,3


(v) f(x) = 5x-π, x=


(vi) f(x) = x2, x=0


(vii) f(x) =1x+m, x=


(viii) f(x) = 2x+1, x =

(i) f(x) = 3x + 1

Put x = -1/3


f (-1/3) = 3 * (-1/3) + 1


= -1 + 1


= 0


Therefore, x = -1/3 is a root of f (x) = 3x + 1


(ii) We have,


f (x) = x2 – 1


Put x = 1 and x = -1


f (1) = (1)2 – 1 and f (-1) = (-1)2 – 1


= 1 – 1 = 1- 1


= 0 = 0


Therefore, x = -1 and x = 1 are the roots of f(x) = x2 – 1


(iii) g (x) = 3x2 – 2


Put x = and x =


g () = 3 ()2 – 2 and g () = 3 ()2 – 2


= 3 * – 2 = 3 * – 2


= 2 0 = 2 0


Therefore, x = and x = are not the roots of g (x) = 3x2 – 2


(iv) p (x) = x3 – 6x2 + 11x – 6


Put x = 1


p (1) = (1)3 – 6 (1)2 + 11 (1) – 6


= 1 – 6 + 11 – 6


= 0


Put x = 2


p (2) = (2)3 – 6 (2)2 + 11 (2) – 6


= 8 – 24 + 22 – 6


= 0


Put x = 3


p (3) = (3)3 – 6 (3)2 + 11 (3) – 6


= 27 – 54 + 33 – 6


= 0


Therefore, x = 1, 2, 3 are roots of p (x) = x3 – 6x2 + 11x – 6


(v) f (x) = 5x –


Put x =


f () = 5 *


= 4 – 0


Therefore, x = is not a root of f (x) = 5x –


(vi) f (x) = x2


Put x = 0


f (0) = (0)2


= 0


Therefore, x = 0 is not a root of f (x) = x2


(vii) f (x) = lx + m


Put x =


f () = l * () + m


= -m + m


= 0


Therefore, x = is a root of f (x) = lx + m


(viii) f (x) = 2x + 1


Put x =


f () = 2 * + 1


= 1 + 1


= 2 0


Therefore, x = is not a root of f (x) = 2x + 1


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