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The value of 'a' for which z= \left ( 2a+3 \right )+i\left ( a-7 \right ) becomes purely real will be \left ( Where\; a\epsilon R \right )

  • Option 1)

    -\frac{3}{2}

  • Option 2)

    7

  • Option 3)

    5

  • Option 4)

    6

 

Answers (1)

best_answer

Complex number will be purely real if imaginary part is zero i.e. a-7=0

\therefore a=7

\therefore Option (B)

 

Purely Real Complex Number -

z=x+iy, x\epsilon R, \boldsymbol{y=0}

& i2=-1

- wherein

Real part of z = Re (z) = x & Imaginary part of z = Im (z) = y

 

 

 


Option 1)

-\frac{3}{2}

This is incorrect

Option 2)

7

This is correct

Option 3)

5

This is incorrect

Option 4)

6

This is incorrect

Posted by

Himanshu

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