If a + b + c = 7 and ab + bc + ca = -6 , then the value of a3 + b3 + c3 – 3abc is:
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Correct answer: D
Explanation
The correct answer is Option 4 i.e 469
Given , a + b + c = 7 (eqn 1)
& ab + bc + ca = -6 (eqn 2)
Now, We know that,
a3 + b3 + c3 - 3abc = (a + b + c) [(a + b + c)2 - 3 (ab + bc + ca)] (Algebraic Identity)
= 7 × [72 - 3(-6)]
= 7 × 67
= 469