New Enroll in RBI Grade B New Batch - Starts on May 21

    Question

    When is the expression 16x - 4x² - 48 greater than

    zero?
    A 1 > x > 3 Correct Answer Incorrect Answer
    B 1 < x < 3 Correct Answer Incorrect Answer
    C 1 ≤ x ≤ 3 Correct Answer Incorrect Answer
    D 1 ≥ x ≥ 3 Correct Answer Incorrect Answer

    Solution

    ATQ,

    So, 16x - 4x² - 48 > 0

    Or, 4x² - 16x + 48 < 0

    Or, 4x² - 12x - 4x + 48 < 0

    Or, 4x(x - 3) -4(x - 3) < 0

    Or, (4x - 4)(x - 3) < 0

    So, x = 1 and x = 3

    Therefore, the expression is positive between 1 and 3.

    Practice Next

    Relevant for Exams: