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9th Class Mathematics Number System and its Operations Question Bank Number System

  • question_answer
    If\[x=2.\overline{3}-0.\overline{9},\,y=2.\overline{5}-0.\overline{5},\]then \[{{x}^{2}}+{{y}^{2}}-2xy\] is

    A)  \[\frac{1}{4}\] 

    B)  \[\frac{1}{3}\]

    C)  \[\frac{1}{2}\]                         

    D)  \[\frac{1}{5}\]

    Correct Answer: A

    Solution :

    (a): \[x=2+\frac{3}{9}-1=\frac{3}{2}\]  \[y=2+\frac{5}{9}-\frac{5}{9}=2\] \[\therefore {{x}^{2}}+{{y}^{2}}-2xy=\frac{9}{4}+4-2.3\times 2\] \[\frac{1}{4}\]              


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