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    If a = 5 + √6, b = 5 - √6, then what is the value of a² + b²?
    Question

    If a = 5 + √6, b = 5 - √6, then what is the value of a² + b²?

    A.

    64

    B.

    60

    C.

    62

    D.

    58

    Correct option is C

    Given:
    a = 5 +6 \sqrt{6}​​
    b = 5 - 6\sqrt{6}​​
    Formula Used:
    (x+y)2=x2+y2+2xy(x + y)^2 = x^2 + y^2 + 2xy​​
    (xy)2=x2+y22xy(x - y)^2 = x^2 + y^2 - 2xy​​
    Solution:
    First, calculate the square of a:
    a2=(5+6)2=25+6+106=31+106a^2 = (5 + \sqrt{6})^2 = 25 + 6 + 10\sqrt{6} = 31 + 10\sqrt{6}​​
    Next, calculate the square of b:
    b2=(56)2=25+6106=31106b^2 = (5 - \sqrt{6})^2 = 25 + 6 - 10\sqrt{6} = 31 - 10\sqrt{6}​​
    Now, add the two squared values together:
    a2+b2=31+106+31106a^2 + b^2 = 31 + 10\sqrt{6} + 31 - 10\sqrt{6}​​
    a2+b2a^2 + b^2​ = 62
    Final Answer
    So the correct answer is (c)

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