Answer :

We need to do hit and trial to find root of a cubic equation.

If it is a root of equation, it must satisfy the equation.


So, let’s start with option A.


(-2)3 + 2(-2)2 - 5(-2)-6 = -8 + 8 + 10 - 6 = 4


Let’s try option B


(2)3 + 2(2)2 - 5(2)-6 = 8 + 8 – 10 - 6 = 0


Let’s try option C


(-3)3 + 2(-3)2 - 5(-3)-6 = -27 + 18 + 15 - 6 = 0


For option D


(3)3 + 2(3)2 - 5(3)-6 = 27 + 18 – 15 - 6 = 24


Hence Option B and C are correct


Verifying –


Factors of the given equation is (x-2)(x + 3)(x + 1) = x3 + 2x2 - 5x - 6.

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