Question

. What are the exact solutions of x2 - x - 4 = 0?

Answer 1

x ² - x - 4 = 0
$x_{1} = \frac{1+ \sqrt{1+16} }{2}= \frac{1+ \sqrt{17} }{2} = 2.56$
$x_{2} = \frac{1- \sqrt{17} }{2}= - 1.56$
Exact values are x 1 = 2.56 and x 2 = -1.56

Answer 2

Answer:

$x=\frac{1+\sqrt{17}}{2}$  and $x=\frac{1-\sqrt{17}}{2}$

Step-by-step explanation:

$x^2 - x - 4 = 0$

To solve for x , apply quadratic formula

$x=\frac{-b+-\sqrt{b^2-4ac}}{2a}$

a=1 , b= -1 , c= -4

Plug in all the values in the formula

$x=\frac{-(-1)+-\sqrt{(-1)^2-4(1)(-4)}}{2(1)}$

$x=\frac{1+-\sqrt{1+16}}{2}$

$x=\frac{1+-\sqrt{17}}{2}$

$x=\frac{1+\sqrt{17}}{2}$  and $x=\frac{1-\sqrt{17}}{2}$