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If roots of ax^{2}+2bx+b= 0 are imaginary \left ( Where\: a\neq 0,\; a,b\epsilon R \right )  then roots of equation bx^{2}+\left ( b-c \right )x+\left ( b-c-a \right )=0 are \left ( c\, \epsilon \, R \right )

  • Option 1)

    real and distinct

  • Option 2)

    real and equal

  • Option 3)

    Imaginary

  • Option 4)

    one real, one imaginary

 

Answers (1)

best_answer

\because first equation has imaginary roots, so 

4b^{2}-4ab< 0\: \Rightarrow \: b^{2}-ab< 0\cdots \cdots \left ( 1 \right )

D of 2nd equation will be

D=\left ( b-c \right )^{2}-4b\left ( b-c-a \right )

\Rightarrow \: D=b^{2}+c^{2}-2bc-4b^{2}+4bc+4ab

\Rightarrow \: D=b^{2}+c^{2}+2bc+4\left ( ab-b^{2} \right )

\Rightarrow \: D=\left (b+c \right )^{2}+4\left ( ab-b^{2} \right )

                       \geq 0                   +ve

\therefore D is positive, So roots are real and Distinct

\therefore Option (A)

 

Complex Roots with non - zero Imaginary part -

D= b^{2}-4ac< 0

- wherein

ax^{2}+bx+c= 0

is the quadratic equation

 

 


Option 1)

real and distinct

This is correct

Option 2)

real and equal

This is incorrect

Option 3)

Imaginary

This is incorrect

Option 4)

one real, one imaginary

This is incorrect

Posted by

Himanshu

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