Question

i^13+i^18+i^31+n=0

Answer 1

\[i^{13}=i^{12} \times i=i\]\[i^{18}=i^{16} \times i^{2}=-1\]\[i^{31}=i^{28} \times i^3=-i\]So,\[i+(-1)-i+n=0\]

Answer 2

you can do it from here. The i s cancel