Question

1) (10 + 5i)³
2) (3i + 7i)(2 + i)
3) (5 + i)²(6 + i)

Помогите решить!

Answer 1

$\boxed {\ i^2=-1\ }\\\\\\(10+5i)^2=100+100i+25i^2=100+100i-25=75+100i\\\\\\(3i+7i)(2+i)=10i\, (2+i)=20i+10i^2=20i-10\\\\\\(5+i)^2(6+i)=(25+10i+i^2)(6+i)=(25+10i-1)(6+i)=\\\\=(24+10i)(6+i)=144+24i+60i+10i^2=144+84i-10=134+84i$