How do you solve $x^2 - 2x - 8 = 0$ ?

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Answer 1 · 2016-04-24T07:35:32

The solutions are:
$x = 4$

$x = -2$

$x^2 - 2x - 8 =0$

The equation is of the form $color(blue)(ax^2+bx+c=0$ where:
$a=1, b=-2, c= -8$

The Discriminant is given by:
$Delta=b^2-4*a*c$

$= (-2)^2-(4*1 * ( -8))$

$= 4 + 32 = 36$

The solutions are found using the formula
$x=(-b+-sqrtDelta)/(2*a)$

$x = (-(-2)+-sqrt(36))/(2*1) = (2+-6)/2$

$x = (2+6)/2 = 8/2 = 4$

$x = (2- 6)/2 = (-4)/2 = -2$

How do you solve x^2 - 2x - 8 = 0x^2 - 2x - 8 = 0?