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    Question

    If (x - y) = 5, then find the value of (x³ - y³ -

    15xy).
    A 75 Correct Answer Incorrect Answer
    B 120 Correct Answer Incorrect Answer
    C 125 Correct Answer Incorrect Answer
    D 150 Correct Answer Incorrect Answer

    Solution

    We know that,
    (x - y³ = x³ - y³ - 3xy(x - y)
    Given, (x - y) = 5
    ⇒ (x - y) ³ = 5³ = 125
    ⇒ x³ - y³ - 3xy × 5 = 125
    ⇒ x³ - y³ - 15xy = 125

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