Question

Multiply (9 − 4i)(2 + 5i).

Answer 1

38+37i

Explanation:

(9 − 4i)(2 + 5i)= 18+45i-8i-20i²= 18+20+37i= 38+37i

Answer 2

38 + 37i

Explanation:

(9 − 4i)(2 + 5i)

FOIL

first: 9*2 = 18

Outer: 9*5i = 45i

inner: -4i * 2 = -8i

last : -4i * 5i = -20i^2 = -20(-1) = 20

Combine together

18+45i-8i +20

38 + 37i