10th Class Mathematics Pair of Linear Equations in Two Variables Question Bank MCQs - Pair of Linear Equations in Two Variables

  • question_answer
    The equations \[\text{2x}-\text{2y}-\text{2}=0\] and \[\text{4x}-\text{4y}-\text{5}=0\] have:   (NCERT EXERCISE)

    A) a unique solution

    B) no solution

    C) infinitely many solutions

    D) None of these

    Correct Answer: B

    Solution :

    [b] Given, \[2x-2y-2=0\] and \[4x-4y-5=0\]
    Here,   \[{{a}_{1}}=2,\,\,{{b}_{1}}=-2,\,\,{{c}_{1}}=-2\]
    and    \[{{a}_{2}}=4,\,\,{{b}_{2}}=-4,\,\,{{c}_{2}}=-5\]
    \[\therefore \,\,\,\,\,\,\,\frac{{{a}_{1}}}{{{a}_{2}}}=\frac{2}{4}=\frac{1}{2},\,\,\frac{{{b}_{1}}}{{{b}_{2}}}=\frac{-2}{-4}=\frac{1}{2}\]and \[\frac{{{c}_{1}}}{{{c}_{2}}}=\frac{-2}{-5}=\frac{2}{5}\]
    \[\Rightarrow \,\,\,\,\,\,\,\,\,\frac{{{a}_{1}}}{{{a}_{2}}}=\frac{{{b}_{1}}}{{{b}_{2}}}\ne \frac{{{c}_{1}}}{{{c}_{2}}}\]
    which shows that the given equations' have no solution.


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