Question

what is 3i(1-i) in a+bi form???
I got 3i-3

Answer 1

What is \(3i*(-i)=\)

Remember, \(i^2=-1\)

Answer 2

-3i(squared) so it's 3???

Answer 3

^yes

Answer 4

Yes. So your new, improved answer is?

Answer 5

3i??? Im sorry this is a hard topic for me am I no right???

Answer 6

What is \(3i*1=\)
What is \(3i*-i=\)
Add them together for your answer

Answer 7

It's just like calculating \(3x(1-x)\) except that after you do so, you replace \(x^2\) with \(-1\)

Answer 8

I mean I got 0i

Answer 9

is that wrong???

Answer 10

Yes, that is incorrect.

\[3i(1-I)=3i*1-3i*i=3i-3i^2=3i-3(-1)=\]

Answer 11

First bit should have been \[3i(1-i)\] but iOS "helpfully" capitalizes it for me...

Answer 12

I got 3i-3 again

Answer 13

Or if you prefer \[3i(1-i)=3(i*1-i*i)=3(i-i^2)=3(i-(-1))=3i+3\]

If you are still getting something else, you need to review manipulation of negative numbers.

Answer 14

I got 3i-3 again

Answer 15

okay thanks i'll just go review with my teacher

Answer 16

-1*-3=

Answer 17

3

Answer 18

Then why aren't you doing that in this problem?!?!?!

Answer 19

I don't know but okay

Answer 20

Look carefully at what I posted

Answer 21

-(-1)=+1

Answer 22

okay

Answer 23

-(-3)=+3

Answer 24

yes I understand that

Answer 25

Then you should be getting the right answer if you pay attention to what you are doing. Can you write out all of your steps for me?

Answer 26

yes

Answer 27

One line t a time, so I can stop you right away

Answer 28

so first I distributed the 3i to 1 and -i... I got 3i-3i^2

Answer 29

Yes, go ahead

Answer 30

then I substituted the i^2 to -1

Answer 31

Show me your work.

Answer 32

I don't know why it is that so many people on OpenStudy, when asked to show their work choose instead to describe it. If we are trying to spot your mistake, we want to see exactly what you did, right?