SolomonZelman 2 years ago x^3+Kx^2+12x-8, is divisible by (x-2) so that the remainder is 4 what is K?

1. hartnn

this is your question or you just testing other's knowledge again ?

2. SolomonZelman

Sorry if that is i nappropriate!

3. SolomonZelman

I'll close the question if this is inappropriate.

4. nincompoop

very inappropriate

5. hartnn

lol, how many times i need to tell you that its not inappropriate, but its not required! and i explained what harm can 'not required' do...

6. SolomonZelman

Close?

7. dan815

|dw:1381783626778:dw|

8. SolomonZelman

OK I'm closing?

9. hartnn

more important is that you do not repeat this again

10. nincompoop

alt+F4 command works better

11. SolomonZelman

I won't do that again if it is inapp...

12. dan815

so u know that

13. SolomonZelman

yep!

14. SolomonZelman

Not this equation, but I can certainly do it.

15. hartnn

see ? you just wasted 2 minutes of dan. thats the harm i am talking about...

16. hartnn

he could have easily helped a needy fellow

17. SolomonZelman

OK I'll close.

18. dan815

lol

19. SolomonZelman

just did

20. SolomonZelman

Sorry guys! Ignore my math questions if other than calc!

21. dan815

|dw:1381783979271:dw|

22. dan815

sign error it shud be -5

23. SolomonZelman

What I am getting is that |dw:1381870420911:dw|

24. SolomonZelman

See why?

25. SolomonZelman

dan815, I don't help, really ignore me!

26. SolomonZelman

b/c remainder is 4, that's how....

27. myininaya

Well we could have done this much easier way... let f be the expression you were fiven f(2)=4 solve for k .... \[2^3+k(2)^2+12(2)-8=8+4k+24-8=4k+24\] 4k+24=4

28. myininaya

Solve for k.

29. SolomonZelman

I knew how to do it from the beginning...closed the question... Sorry!

30. myininaya

I just wanted to make sure you guys know it wasn't as complicated as you were making it. :P

31. SolomonZelman

For sure not! Another way to do it is synthetic division... -8+2(16+2)k=4 -the remainder I get it don't worry.

32. myininaya

Yep. That is a way to do it but I think it easier to do if given (poly of higher degree than 0)/(x-c), then all we need to do is that poly evaluated at c to find the remainder. f(c)=Remainder

33. SolomonZelman

Yes. U see what i did..... I know it 100% don't worry.

34. myininaya

Ok. I'm not worried. I'm only responding here because I wanted to.

35. myininaya

And also just in case someone else can learn from it.

36. SolomonZelman

let other ppl... they do

37. myininaya

What?

38. SolomonZelman

know this, since they came to help..... But true, they were making it much more complicated than what it is.

39. SolomonZelman

40. SolomonZelman

WHATEVER.

41. myininaya

Ok....

42. dan815

lol

43. dan815

calm down guys none of us like PHD students here -.- we're all noobs believe it or not

44. myininaya

lol. I was just trying to help....

45. hartnn

on a lost cause :P

46. myininaya

Looks like it.

47. dan815

well it was helpful! i didnt think of just subbing in 2

48. myininaya

49. dan815

:)

50. dan815

how did u know that subbing in that value gives you the remainder though? like the way if its 0 then it is a good factor

51. myininaya

Theorems.

52. myininaya

I actually think it is called the remainder theorem.

53. dan815

oh ive heard of that before, thanks!

54. myininaya