8th Class Mathematics Algebraic Expressions Question Bank Algebra

  • question_answer
    Factors of \[{{x}^{2}}+\frac{1}{{{x}^{2}}}+2-2x-\frac{2}{x}\] are

    A)  \[x-\frac{1}{x}\]  

    B)  \[x+\frac{1}{x}-1\]

    C)  \[x+\frac{1}{x}\]

    D) None of these

    Correct Answer: B

    Solution :

    \[4{{x}^{2}}-20x+25=0\] \[\frac{3}{2}\] \[=(2{{a}^{2}}+2ab)+(2{{b}^{2}}+2ab)+(a+b)-(10a+10b+5)\] \[\frac{7}{2}\] \[\frac{7}{2}\] \[\frac{5}{2}\] Another way Let  \[a+b=x\] Then, \[2{{(a+b)}^{2}}-9(a+b)-5=2{{x}^{2}}-9x-5\] \[\Rightarrow \] \[2{{x}^{2}}-10x+x-5\]  \[\Rightarrow \]\[2x\,(x-5)+1\,(x-5)\] \[a+b+c=9\] Put the value of \[ab+bc+ca=26,\] \[{{a}^{3}}+{{b}^{3}}+{{c}^{3}}-3abc\] \[x:\frac{x-a}{b+c}+\frac{x-b}{c+a}+\frac{x-c}{a+b}=3\]


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