Question

Simplify: (-4i+13)(-i-1)
A. 17i-9
B. -9i-17
C. -17+9i
D. 9+17i
E. none of these.

I'm getting E. none of these, the answer I'm coming out with is -17-9i

Answer 1

we have:
\[(-4i+13)*(-i-1)=(-4i)*(-i-1)+13*(-i-1)=-4+4i-13i-13=-17-9i\]

Answer 2

oops:
\[=-4+4i-13i-13=-17-9i\]

Answer 3

So B.

Answer 4

D

Answer 5

wait nvm B

Answer 6

@Michele_Laino but the order of it is different. it's okay to switch it around like that?

Answer 7

yes, you can write a complex number in this form: a+ib, or in this form: ib+a, in both cases the complex number is the same

Answer 8

@clynnew