Question

If z = 3+5i, then $z^3$ + $\overline{z}$ + 198 =

• A. -3-5i
• B. -3+5i
• C. 3+5i
• D. 3-5i

Answer 1

The correct option is C

3+5i

z = 3+5i , $\overline{z}$ = 3-5i

⇒ $z^3=(3+5i{)}^3=3^3+(5i{)}^3+\mathrm{3.3.5}i(3+5i)$

= -198+10i

Hence, $z^3+\overline{z}$ + 198 = 10i-198+3-5i+198 = 3+5i .