## Destinyyyy one year ago Perform the addition (-9/2 +1/2i) + (3/2 - 7/2i)

1. anonymous

My example shows to put the i on the outside of the equation like this- (-9/2 +1/2) + (3/2 - 7/2)i Im not sure what to do next

2. UsukiDoll

I wouldn't do it like that. Our answer has to be in the form of ai+b or a+bi... the same rule applies for subtraction ai-b or a-bi so what I would've done is to combine the like terms as in put all the terms without the i's to the left and all terms with the i's to the right

3. UsukiDoll

$\frac{-9}{2}+\frac{3}{2}+\frac{1}{2}i-\frac{7}{2}i$

4. UsukiDoll

now the denominators are the same which is good because we don't have to use GCF or LCD ... so can you tell me what -9+3 is? and 1-7 ?

5. anonymous

-6

6. UsukiDoll

alright so now we have $\frac{-6}{2}+\frac{-6}{2}i$ so what's -6 divided by 2

7. anonymous

Im trying to follow but Id like to follow the examples with the i on the outside

8. UsukiDoll

you need to rearrange the terms a bit before you can factor the i outside.

9. anonymous

I did another problem like this-- (-5+5i) + (9+8i) = (-5+5) + (9+8)i -5+9 + 5+8 4 + 13i

10. UsukiDoll

there's a problem with that

11. anonymous

What would that be?? The answer is correct

12. UsukiDoll

(-5+5i)+(9+8i) you have to rearrange the terms first it should look something like this -5+9+5i+8i and then it would be 4+13i which is right, but you need to do some rearranging first

13. UsukiDoll

either combine like terms or take the i outside -5+9+(5+8)i 4+13i

14. UsukiDoll

the same goes with this $\frac{-9}{2}+\frac{3}{2}+\frac{1}{2}i-\frac{7}{2}i$ $\frac{-9}{2}+\frac{3}{2}+(\frac{1}{2}-\frac{7}{2})i$

15. UsukiDoll

O_O! What happened to my latex? -____-! OS is acting up.

16. anonymous

All of my examples do it with the i on the outside so its easier for me to understand

17. anonymous

latex?

18. UsukiDoll

there's more than one method to doing this problem and it all gives the same result as long as you do the correct arithmetic.

19. anonymous

Okay

20. anonymous

Im following you now

21. UsukiDoll

let me rewrite the top portion... it's not displaying right

22. anonymous

Okay

23. UsukiDoll

$\frac{-9}{2}+\frac{1}{2}i+\frac{3}{2}-\frac{7}{2}i$ $\frac{-9}{2}+\frac{3}{2}+\frac{1}{2}i-\frac{7}{2}i$ [rearrange the terms] $\frac{-9}{2}+\frac{3}{2}+(\frac{1}{2}-\frac{7}{2})i$ [factor the i so it appears on the outside] $\frac{-6}{2}+(\frac{-6}{2})i$ [solve for the numerators] last step is division

24. UsukiDoll

-6/2 = ?

25. anonymous

-3

26. UsukiDoll

$-3-3i$ yup and we're done :)

27. anonymous

Okay thank you!