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

  • question_answer
    The graphs of the equations \[\text{6x}-\text{2y}+\text{9}=0\] and \[\text{3x}-\text{y}+\text{12}=0\] are two lines which are:

    A) coincident

    B) parallel

    C) intersecting exactly at one point

    D) perpendicular to each other

    Correct Answer: B

    Solution :

    [b] Here, \[{{a}_{1}}=6,\,\,{{b}_{1}}=-2,\,\,{{c}_{1}}=9\]
    and  \[{{a}_{2}}=3,\,\,{{b}_{2}}=-1,\,{{c}_{2}}=12\]
    \[\therefore \frac{{{a}_{1}}}{{{a}_{2}}}=\frac{6}{3}=\frac{2}{1},\,\,\frac{{{b}_{1}}}{{{b}_{2}}}=\frac{-2}{-1}=\frac{2}{1}\]and \[\frac{{{c}_{1}}}{{{c}_{2}}}=\frac{9}{12}=\frac{3}{4}\]
    Hence, \[\frac{{{a}_{1}}}{{{a}_{2}}}=\frac{{{b}_{1}}}{{{b}_{2}}}\ne \frac{{{c}_{1}}}{{{c}_{2}}}\]
    So. the lines are parallel


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