can anyone solve, x squared - x - 1= 0?

Answer 1

The answers are:

1.618033989
-0.618033989

( half of (1 plus or minus the square root of 5))

The quadratic formula and how it is derived is here:
http://www.sosmath.com/algebra/quadraticeq/quadraformula/quadraformula.html

Answer 2

x=1

Answer 3

1-1=0 x=1

Answer 4

Yes, but whats the point if I solve it? You need to solve it using the quadratic formula. It is easy, all you need to do is replace a, b and c with the correct corresponding coefficients. If you have a TI-83 Plus, it contains the program, namely "QUADFORM" when you push the "APPS" button. This program will simply ask the A, B, and C values and calculate it for you in a blink of a eye. BUT! you will fail your exams miserably if you do not learn these fundamental formulas and concepts of math.

Anyhow, if you really need the answer, and cant find it.. here it is:

X = {-0.61803, 1.618) which means 2 values can be placed for X for the equation to work out. Some other pertinent information is:

Answer in fractional form: { 1 ± Sq Root ( 1 + 4 ) } ÷ 2
- Equation's Graph Is Concave UP or U shaped
- Equation's Derivative Is 2 X -1
- Minimum Is at X = 0.5 and Y = -1.25
- Equation's Integral= (1 X^3)/3 (-1 X^2)/2 -1 X
- Area Under X-Axis= 1.8634

I hope this helps you to understand the importance in math, and I hope you didnt look straight to the answer. Math is crucial, even though it may seem not to be. LEARN YO MATH!

Answer 5

to solve x ^ 2 - x - 1 = 0 use the quadratic formula with the following substitutions
a = 1 , b = -1 , c = -1
Plug in the values, do the arithmetic and you will get the two answers:
1.618 and -0.618 (to 3 decimal places).

Answer 6

1plus or minus(1-4*1*-1) so it will be 1 + or - 5 then that over 2
6/2 and-4/2 so it is 3 and -2 used the eqatric formula

Answer 7

well yea u have x^2 then subtract an x so then u have x which is the same as 1 and then u subtract 1 which gives u 0

Answer 8

your question is:

X² - X - 1 = 0

Using Quadratic formula, u can easiy solve it
--------------------------------------------------------
If we have a form aX² + bX + C = 0

then X = [-b ± √(b²-4ac)]/2a
---------------------------------------------------------
for your equation, a =1 , b=-1 and c=-1

by putting these values in quadratic foruma we get.

X = [-b ± √(b²-4ac)] / 2 a

X = [-(-1) ± √(-1² -4(1)(-1))] / 2(1)

X = [+1 ± √( 1+4)] / 2

X= [+1 ± √5]/2

so X=(1+√5)/2 and X = (1-√5)/2 Answers

X= (1.6180) and X =(-0.61803) Answers

Answer 9

Don't know why there are so many trash answers to this. Using the quadratic formula, we obtain two real but irrational roots: 1 +/- (sqrt(5)/2).

Answer 10

Sure, using the quadratic formula, you get

x = (sqrt(5)+1)/2 or x = -(sqrt(5)-1)/2