How do you solve $x^2 – 3x – 1 = 0$ using the quadratic formula?

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Answer 1 · 2017-05-31T00:08:35

Using the quadratic formula, $x$ can either $=-2.618 or -0.382$

$a x^2 + bx + c = 0$

$1 x^2 + 3x + -1 = 0$

$a = 1$
$b = 3$
$c = -1$

$x = (-b +- sqrt(b^2-4ac))/(2a)$

$x = (-3 +- sqrt(3^2-4 xx 1 xx -1))/(2 xx 1)$

$x = (-3 +- sqrt(9- 4))/2$

$x = (-3 +- sqrt5)/2$

$x = (-3 +- 2.236)/2$

$x_1 = (-3 - 2.236)/2$

$x_1 = (-5.236)/2$

$color(blue)(x_1 = -2.618$

$x_2 = (-3 + 2.236)/2$

$x_2 = (-0.764)/2$

$color(blue)(x_2 = -0.382$

How do you solve x^2 – 3x – 1 = 0x^2 – 3x – 1 = 0 using the quadratic formula?