Question

Okay so I'm completely lost.... Does anybody understand operations of on complex numbers? Basically problems like (0-2i)-(8-6i)??? Thanks!

Answer 1

well its just like algebra... its about collecting like terms.

so remove the backets and you ge

0 - 2i - 8 + 6i

collect the like terms

( 0 - 8) + (-2i + 6i)

hopefully this allows you to find the answer.

Answer 2

Wouldn't removing the brackets put it to
0-2i-8-6i???

Answer 3

well you need to distribute -1

so in the 2nd set of brackets its

-1(8 - 6i)

is

-1 x 8 = -8

-1 x -6i = 6i

hope that helps

Answer 4

@xXxBambyGirlxXx
( 0 - 2i) - (8 - 6i )
is like ( 0 - 2i) -1 (8 - 6i ) --> so there you will need to substitute -1
then it will become (0 - 2i) + (-8+6i), right?
then removing the parentheses will give you 0-2i-8+6i
which is equal to 4i-8 or is also similar to 4 (i - 2)

Answer 5

I'm lost.... /:

Answer 6

ok... so look at the 2nd set of brackets

is

\[-1 \times (8 - 6i)\]

can you distribute the -1...?

Answer 7

By making -8+6i?

Answer 8

thats correct.... and the 1st set of brackets is

\[1 \times (0 - 2i)\]

can you distribute that..?

Answer 9

It would just be 0-2i correct?

Answer 10

JUST TREAT I AS ANY VARIABLE AND JUST OPEN THE BRACKETS AND SOLVE
JUST REMEMBER THAT REAL AND IMAGINARY PARTS DO NOT ADD OR SUBTRACT WITH EACH OTHER

Answer 11

ANSWER WOULD BE -8+4i

Answer 12

thats correct... so after distributing it looks like

0 - 2i - 8 + 6i

now collect the like terms...

Answer 13

-8+4i!(:

Answer 14

thats it.... just like those basic algebra classes where you collected like terms...

well done

Answer 15

Could you walk me through the next one?..

Answer 16

ok... if you post it in the normal way I'll look at it...

Answer 17

Multiply..
(6+4i)(5-9i)

Answer 18

ok... so I'll do this the long way by splitting the 1st brackets...

\[6(5 - 9i) + 4i(5 - 9i)\]

can you distribute them...?

Answer 19

Okay okay so...
30-54i+20i-36i??

Answer 20

thats great... but the last term is 36i^2...

does that make sense...?

Answer 21

so the problem is now

30 - 54i + 20i - 36i^2

Answer 22

Ohhh yeah I thought so!

Answer 23

ok... cool...

now do you know about

i^2 = -1...?

Answer 24

Okay so combine like terms...
No so it would basically be
30-54i+20i-36??

Answer 25

and substituting... before simplifying you get

\[30 - 54i + 20i - 36 \times (-1) = 30 -54i + 20i + 36\]

does that make sense...?

Answer 26

now you can combine the like terms...

Answer 27

Okay okay!
so 66-34i??

Answer 28

thats it... well done

Answer 29

So would (5-3i)(2-8i) come out to be:
-14-46i?

Answer 30

yes... that looks great... well done

took me a minute to do it in my head

Answer 31

Haha now addition... Help me one last time?

Answer 32

ok... as long as it's quick... post the question and you're solution

Answer 33

(4-2i)+(12+7i)
I'm not sure where to start on this one /:

Answer 34

-8+9i?

Answer 35

ok... so with both sets of brackets its

\[1 \times (4 - 2i) + 1 \times (12 + 7i) = 4 - 2i + 12 + 7i\]

collect the like terms...

Answer 36

so you get

4 + 12 +7i - 2i =

can you finish..?

Answer 37

16+5i?

Answer 38

thats it.... well done