2017 SSC CGL 20 Aug Shift-1

Question 87

If a + b = 1 and ab = -6, then what is the value of $$a^{3} + b^{3}$$ ?

Solution

$$a^{3} + b^{3} = (a+b)^{3} - 3ab(a+b)$$

$$a^{3} + b^{3} = (1)^{3} - 3(1)(-6) = 1 + 18 = 19$$

So thre answer is option C.

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