Question

    If a + b = 8 and ab = 5, then what is the value of a³ +

    b³?
    A 552 Correct Answer Incorrect Answer
    B 685 Correct Answer Incorrect Answer
    C 392 Correct Answer Incorrect Answer
    D 450 Correct Answer Incorrect Answer
    E None of these Correct Answer Incorrect Answer

    Solution

    ATQ;
    Given, a + b = 8, and ab = 5
    So, a³ + b³ = (a + b)³ - 3ab(a + b) = 8³ - 3 * 5 * 8 = 512 - 120 = 392

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