Question

Simplify the following product of complex  numbers

(4 - 8i) * (-5 + 2i)

Answer 1

Multiplication in complex numbers (a+bi)(c+di) = (ac-bd)+(bc+ad)i

(4-8i)*(-5+2i)

Here a = 4, b =-8, c = -5, d = 2

= [(4*-5)-(-8*2)]+[(-8*-5)+(4*2)]i

= [-20+16]+[40+8]i

= -4+48i