Д)1+3i/2-i = (1+3i)(2+i)/(2-i)(2+i)= (2+i+6i+3i^2)/(4-i^2)= (2+7i-3)/(4+1)= -1+7i/5= -1/5 + 7/5*i
А)(4+5i)(4-5i) = 44 + 4(-5i) + 5i4 - 5i(-5i)= 16 - 20i + 20i + 25= 41
Д)
1+3i/2-i = (1+3i)(2+i)/(2-i)(2+i)
= (2+i+6i+3i^2)/(4-i^2)
= (2+7i-3)/(4+1)
= -1+7i/5
= -1/5 + 7/5*i
А)
(4+5i)(4-5i) = 44 + 4(-5i) + 5i4 - 5i(-5i)
= 16 - 20i + 20i + 25
= 41