First, lets solve the equation using notable product:
[tex]\begin{gathered} (4+6i)^2 \\ =4^2+2\cdot4\cdot6i+(6i)^2 \\ =16+48i+36^{}i^2 \\ ^{} \\ \text{ Since i}^2=-1,\text{ we can substitute it in equation: } \\ =16+48i+36^{}(-1) \\ =16+48i-36 \\ =-20+48i \end{gathered}[/tex]Answer: alternative a
