Answer :
Answer:
- 5i.
Step-by-step explanation:
( 1 + 2 i ) ( − 2 − 1 i )
= 1 * -2 + 1*-1i + 2i*-2 - 2i*1i
= -2 - i - 4i - 2i^2 i^2 = -1 so we have:
-2 - 5i +2
= 0 - 5i
= -5i.
Answer:
- 5i.
Step-by-step explanation:
( 1 + 2 i ) ( − 2 − 1 i )
= 1 * -2 + 1*-1i + 2i*-2 - 2i*1i
= -2 - i - 4i - 2i^2 i^2 = -1 so we have:
-2 - 5i +2
= 0 - 5i
= -5i.