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

    Question

    If x4 + x2 y2 +

    y4 = 37 and x2 – xy + y2 = 5, then what is the value of xy ?
    B -1 Correct Answer Incorrect Answer
    C 1.2 Correct Answer Incorrect Answer
    D -1.2 Correct Answer Incorrect Answer

    Solution

    x4+ x2 y2 + y2= 37 and x2– xy + y2= 5 --- (1) As we know, (x4+ x2 y2 + y2) = (x2– xy + y2) (x2+ xy + y2) ⇒ x2+ xy + y2= 37/5 ⇒ x2– xy + y2= 7.4 --- (2) Subtract equation (2) from equation (1) ⇒ 2xy = 2.4 ⇒ xy = 1.2

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