## mathhelp23 Group Title solve 3x^2-5x-11=0 find the x intersepts of f(x)=3x^2-5x-11. 2 years ago 2 years ago

1. Hero Group Title

It's not complex

2. Hero Group Title

$D = b^2 - 4ac = (-5)^2 - 4(3)(-11) = 25 + 132 = 157$

3. Hero Group Title

$x = \frac{\pm \sqrt{157} + 5}{6}$

4. mathg8 Group Title

any method ?

5. mathhelp23 Group Title

thank you

6. krypton Group Title

@Hero that's the answer i got,dat's why i called it a complex root

7. mathg8 Group Title

@krypton : square root of a negative number gives you a complex number solution

8. myininaya Group Title

any number is complex

9. myininaya Group Title

4 is complex 4i is complex 4+4i is complex

10. mathg8 Group Title

4+0i

11. mathg8 Group Title

why do we have real and complex sets then ?

12. myininaya Group Title

real numbers is a subset of the complex imaginary numbers is a subset of the complex

13. myininaya Group Title

all numbers are complex

14. mathg8 Group Title

If a complex number has b = 0, then it is a real number and it lies on the real axis in the complex plane

15. myininaya Group Title

Definition of Complex: $Complex =\{a+bi | a \in \mathbb{R} , b \in \mathbb{R}\}$

16. Hero Group Title

Define complex in words only without using mathematical notation.

17. Hero Group Title

What a meant to say is that the discriminant yields a real number, not a complex number. The definition of a complex number is a + bi

18. mathg8 Group Title

The real line can be thought of as a part of the complex plane, and correspondingly, complex numbers include real numbers as a special case.

19. mathg8 Group Title

... Special Case

20. Hero Group Title

That's good to know. I'm not the one confused about it.

21. myininaya Group Title

Excuse me?

22. myininaya Group Title

I'm not confused either.

23. Hero Group Title

I know you're not myininaya. I never said you were :P

24. mathg8 Group Title

def : A complex number is neither purely real nor purely imaginary, but rather is a composite of the two ! Happy everyone ?

25. myininaya Group Title

Ok I guess I just understood you. sorry hero. :)

26. myininaya Group Title

misunderstood you* lol

27. myininaya Group Title

real numbers are complex imaginary numbers are complex real numbers+imaginary numbers are still complex

28. Hero Group Title

she avoided using the word "pure" in her definitions.

29. myininaya Group Title
30. Hero Group Title

So myininaya, which numbers are purely complex?

31. myininaya Group Title

I don't have a definition for "purely" complex numbers as I never heard of any set of numbers being defined at such sorry

32. mathg8 Group Title

check out this book : An imaginary tale The Story of √-1 by Paul J. Nahim ( Professor Emeritus of Electrical Engineering at the University of New Hampshire )

33. Hero Group Title

Guess there's no such thing as a pure complex number since it is a "mixture" of pure real and pure imaginary.

34. mathg8 Group Title

4 is real 4+0i is complex

35. myininaya Group Title

4=4+0i

36. myininaya Group Title

4/2 is an integer just like 2 is

37. myininaya Group Title

because 4/2=2

38. myininaya Group Title

@jamesj @zarkon

39. Hero Group Title

Why are you two reciting stuff you already know? Because I already know this stuff

40. mathg8 Group Title

|dw:1331351848500:dw|

41. mathg8 Group Title

this is interesting ... LOL

42. Hero Group Title

mathg8, I guess you really want krypton to understand

43. mathg8 Group Title

I just never heard this before ... so it is interesting ( not wrong or right ) just interesting ...

44. mathg8 Group Title

real numbers are complex ( i meant this statement )

45. krypton Group Title

lol intresting :)

46. Hero Group Title

Krypton, I'm sure you enjoyed this

47. krypton Group Title

lol yeah! alot,just woke up from sleep and logged in,only to find some argument in here.was fun :)

48. mathg8 Group Title

yes ... this was fun!