Question

Let `z=9+b i ,w h e r eb` is nonzero real and `i^2=-1.` If the imaginary part of `z^2a n dz^3` are equal, then `b//3` is ______.

Answer 1

Correct Answer - 15
`z^(2) = 81 - b^(2) + 18bi`
`z^(3) = 729 + 43bi - 27b^(2) - b^(3)i`
`rArr = 243b -b^(3) = 18b`
`rArr b = 15`