## Destinyyyy one year ago Possible help with a few questions (refresher and check)

1. Destinyyyy

Divide and express the result in standard form. 6i/9-8i

2. Destinyyyy

I got -48+54i/145 but im incorrect

3. Saurabh135

i thnk u right..

4. Destinyyyy

It says the correct answer is --> - 48/145 + 54i/145

5. Saurabh135

oh...then tell me can't u write (a+b)/c= a/c + b/c

6. Saurabh135

oh...then tell me can't u write (a+b)/c= a/c + b/c

7. Destinyyyy

I thought it was the same thing

8. phi

standard form for a complex number is a + bi where a is the real part and b the imag part. they want you to divide through by the 145 so that you have a real part -48/145 and an imaginary part 54/145 i

9. Destinyyyy

Okay so I have to write it separate like that when it says standard form with a fraction?

10. Saurabh135

yeah u hv to seperate in form of a+ib

11. phi

yes

12. Destinyyyy

Great more stuff I have to remember.. Okay thank you for explaining that

13. phi

yes, math has a lot of memorizing. but it's not like learning French ... it seems like they have a different word for everything.

14. Destinyyyy

True.

15. Destinyyyy

Perform the indicated operation and write in standard form a+bi. 5 square root -64 + 6 square root -25 .... I cant remember how to solve this one -.-

16. Destinyyyy

@phi

17. phi

write the $$\sqrt{-64}$$ as $$\sqrt{64}\cdot \sqrt{-1}$$

18. anonymous

$5\sqrt{-64} + 6\sqrt{-25}$$=5\sqrt{64}\sqrt{-1}+6\sqrt{25}\sqrt{-1}$This help any?

19. phi

and use the short-hand "i" for sqr(-1)

20. Destinyyyy

That turns into 5 square root 64i +6 square root 25i right? Or am I way off?

21. phi

yes, but sqr(64) is a nice number ditto sqr(25)

22. anonymous

Yes, but you know sqrt(64) and sqrt(25)

23. anonymous

Sorry. I'm out. Keep up the good work.

24. Destinyyyy

So now I have to make them into smaller numbers...

25. phi

yes. you should know them, but you can use a calculator if you don't

26. Destinyyyy

8i and 5i

27. phi

ok, and you now have 5*8*i + 6*5*i (I put in the multiply signs to make it clearer) that can be simplified.

28. Destinyyyy

40i+30i 70i^2 70(-1) -70

29. phi

it is 40 i's plus 30 more i's

30. Destinyyyy

Oops so its 70i

31. phi

yes

32. Destinyyyy

Okay thank you... 3 more to go