Question

Simplify the given expression.

(6 + 2i) − (8 − 3i)

Answer 1

ahhh must be in ai+b or a+bi form

Answer 2

−2 + 5i

−2 − i

8 + 5i

8 − 5i

Answer 3

distribute the negative on the right hand side of the equation ... combine like terms.. there's the format ^^

Answer 4

(6 + 2i) − (8 − 3i)
6+2i-8+3i = -2+5i

Answer 5

how'd you add them together? i tried foil but i didnt get the right thing

Answer 6

no there's no foil in here. just normal subtraction and combining like terms

Answer 7

foil works for (x+y)(x-y) no sign in the middle

Answer 8

ohh

Answer 9

can you help with one more? Simplify the given expression.

2 divided by the quantity of 2 plus 5i

Answer 10

hmm :/ I can't see it very well

Answer 11

argh I forgot how those work...

Answer 12

I know you can't split them up... nooo that breaks the rules

Answer 13

Couple of things to know here:
1) i=Sqrt(-1), i^2=-1
2) (a+b)(a-b) = a^2 - b^2, with no middle term
3) the goal of this problem is to eliminate the complex number 2 +5i from the denominator.
4) 2-5i is called the "conjugate" of 2+5i.
5) Applying principles from (1) and (2), above, (2-5i)(2+5i)=4-25i^2
which simplifies to 4-25(-1) = 29.
6) multiply both numerator and denominator of the given expression by the conjugate in (4) and simplify the result.

2(2-5i) 2(2-5i)
------- = --------- is the simplest form the answer you want.
4-25(-1) 29

There's no real benefit from multiplying out 2(2-5i).

Answer 14

Notice how the denominator is now real, whereas before it was complex.

Answer 15

so you just multiply the numerator by the conjugate? then simplify fro mthere?

Answer 16

Also notice that the first problem you presented was one in subtraction of complex numbers; the second was more complicated because of the multiplication of complex numbers required.

@skipper16: Multiply BOTH the numerator and the denominator of the given fraction by the conjugate (2-5i).

Answer 17

This process may be referred to as "rationalizing the denominator".

Answer 18

now I remember...

Answer 19

Hmm

Answer 20

Thank you very much for the medal.

Answer 21

you're welcome thanks for the help

Answer 22

:O where's my medal?