How do you solve $5x^2 - 2x – 2 = 0$ ?

Question

8802 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2015-08-12T06:17:56

The solutions are:

$color(blue)(x= (1+sqrt11)/5$

$color(blue)(x= (1-sqrt11)/5$

$5x^2−2x – 2=0$

The equation is of the form $color(blue)(ax^2+bx+c=0$ where:
$a=5, b=-2, c=-2$

The Discriminant is given by:

$color(blue)(Delta=b^2-4*a*c$

$= (-2^2)-(4*5*(-2))$

$=4+40$

$= 44$

The solutions are found using the formula:

$color(blue)(x=(-b+-sqrtDelta)/(2*a)$

$x = (-(-2)+-sqrt(44))/(2*5) = (2+-2sqrt(11))/10$

$=(cancel2(1+-sqrt11))/cancel10 = (1+-sqrt11)/5$

The solutions are:

$color(blue)(x= (1+sqrt11)/5$

$color(blue)(x= (1-sqrt11)/5$

How do you solve 5x^2 - 2x – 2 = 05x^2 - 2x – 2 = 0?