Answer:
add, subtract, multiply and divide complex numbers much as we would expect. We add and subtract 
complex numbers by adding their real and imaginary parts:- 
(a + bi)+(c + di)=(a + c)+(b + d)i, 
(a + bi) − (c + di)=(a − c)+(b − d)i. 
We can multiply complex numbers by expanding the brackets in the usual fashion and using i 
2 = −1, 
(a + bi) (c + di) = ac + bci + adi + bdi2 = (ac − bd)+(ad + bc)i, 
and to divide complex numbers we note firstly that (c + di) (c − di) = c2 + d2 is real. So 
a + bi 
c + di = a + bi 
c + di × 
c − di 
c − di = 
µac + bd 
c2 + d2 
¶ 
+ 
µbc − ad 
c2 + d2 
¶ 
i. 
The number c−di which we just used, as relating to c+di, has a spec