If a + b + c = 8 and ab + bc + ca = 20, then a3+ b3+ c3– 3abc is equal to?
Show answer & explanation
Correct answer: B
Explanation
Correct Answer is option 2 i.e. 32
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Concept |
Understanding |
Application |
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a3 + b3 + c3 – 3abc = (a + b + c) [(a + b + c)2 – 3(ab + bc + ca)] |
Given, a + b + c = 8 and ab + bc + ca = 20 |
Applying the formula: a3 + b3 + c3 – 3abc = 8× [82 – 3 × 20] = 8× (64 – 60) = 32 |