Question

Z1=2+5i z2=1-i
Найти z1+z2; z1-z2; z1:z2;z1*z2

Answer 1

$z_1+z_2=2+5i+1-i=(2+1)+(5-1)i=3+4i$

$z_1-z_2=2+5i-1+i=(2-1)+(5+1)i=1+6i$

$z_1:z_2= frac{2cdot 1+5cdot (-1)}{1^2+(-1)^2} +(frac{5cdot 1+2}{1^2+(-1)^2} )i=-1.5+3.5i$

$z_1cdot z_2=(2cdot1-5cdot (-1))+(5cdot 1+2cdot(-1))i=7+3i$