1.
1)-5+и+2+5и=-3+6и
2)-5+и-2-5и=-7-4и
3)(-5+и)(2+5и)=-10-25и+2и-5=-15-23и
4)(-5+и)(2-5и)/(2+5и)(2-5и)=-5+27и)/29=-5/29+27и/29

3.б) 1+3и/3-3и-2и-2=(1+3и)/(1-5и)=(1+3и)(1+5и)/(1-5и)(1+5и)=(1+5и+3и-15)/(1+25)=-14/26+8и/26=-7/13+4и/13