6th Class Mathematics Algebra Question Bank Algebra

  • question_answer
    What is the value of \[a{{x}^{2}}+bx+c\] at \[x=-\frac{b}{a}\]?

    A)  a                    

    B)    0

    C)  c                    

    D)    \[{{b}^{2}}-4ac\]

    Correct Answer: C

    Solution :

         \[a{{x}^{2}}+bx+c=a\,{{\left( -\frac{b}{a} \right)}^{2}}\,+b\left( -\frac{b}{a} \right)+c\] \[=\frac{a{{b}^{2}}}{{{a}^{2}}}-\frac{{{b}^{2}}}{a}+c\] \[=\frac{{{b}^{2}}}{a}\,-\frac{{{b}^{2}}}{a}+c=c\]


You need to login to perform this action.
You will be redirected in 3 sec spinner