Question

solve
3x^2-5x-11=0
find the x intersepts of f(x)=3x^2-5x-11.

Answer 1

It's not complex

Answer 2

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

Answer 3

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

Answer 4

any method ?

Answer 5

thank you

Answer 6

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

Answer 7

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

Answer 8

any number is complex

Answer 9

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

Answer 10

4+0i

Answer 11

why do we have real and complex sets then ?

Answer 12

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

Answer 13

all numbers are complex

Answer 14

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

Answer 15

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

Answer 16

Define complex in words only without using mathematical notation.

Answer 17

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

Answer 18

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.

Answer 19

... Special Case

Answer 20

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

Answer 21

Excuse me?

Answer 22

I'm not confused either.

Answer 23

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

Answer 24

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

Answer 25

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

Answer 26

misunderstood you* lol

Answer 27

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

Answer 28

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

Answer 29

http://en.wikipedia.org/wiki/Complex_number

Answer 30

So myininaya, which numbers are purely complex?

Answer 31

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

Answer 32

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 )

Answer 33

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

Answer 34

4 is real
4+0i is complex

Answer 35

4=4+0i

Answer 36

4/2 is an integer
just like 2 is

Answer 37

because 4/2=2

Answer 38

@jamesj @zarkon

Answer 39

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