Use the Factor Theorem to determine whether g(x) is a factor of p(x) in each of the following cases:

(i)


(ii)


(iii)


(i) If g (x) = x + 1 is a factor of given polynomial p (x), p (-1) must be zero

p (x) = 2x3 + x2 – 2x – 1


p (-1) = 2 (-1)3 + (-1)2 – 2 (-1) – 1


= 2 (-1) + 1 + 2 – 1 = 0


Hence, g (x) = x + 1 is a factor of given polynomial


(ii) If g (x) = x + 2 is a factor of given polynomial p (x), p (-2) must be zero


p (x) = x3 + 3x2 + 3x + 1


p (-2) = (-2)3 + 3(-2)2 + 3 (-2) + 1


= -8 + 12 - 6 + 1 = -1


As, p (-2) ≠ 0


Hence, g (x) = x + 2 is not a factor of given polynomial


(iii) If g (x) = x – 3 is a factor of given polynomial p (x), p (3) must be zero


p (x) = x3 – 4x2 + x + 6


p (3) = (3)3 – 4 (3)2 + 3 + 6


= 27 – 36 + 9 = 0


Therefore, g(x) = x – 3 is a factor of the given polynomial


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