182. Perform the operations: a) $(2+3 i)^{2} ;$ b) $(3-5 i)^{2}$; c) $(5+$ $+3 i)^{3}$
Solution. $\quad$ a) $\quad(2+3 i)^{2}=4+2 \cdot 2 \cdot 3 i+9 i^{2}=4+12 i-9=-5+$ $+12 i$

b) $(3-5 i)^{2}=9-2 \cdot 3 \cdot 5 i+25 i^{2}=9-30 i-25=-16-30 i$;

c) $(5+3 i)^{3}=125+3 \cdot 25 \cdot 3 i+3 \cdot 5 \cdot 9 i^{2}+27 i^{3}$;

since $i^{2}=-1$, and $i^{3}=-i$, we get $(5+3 i)^{3}=125+225 i-135-$ $-27 i=-10+198 i$.

183-190. Perform the operations: