Question

Solving Quadratic Equations posttest

A.
B.
C.
D.

Answer 1

Answer:

D. $x = 3 \pm \sqrt{10}$

Step-by-step explanation:

$x^2 - 6x - 1 = 0$

$x = \dfrac{-b \pm \sqrt{b^2 - 4ac}}{2a}$

a = 1; b = -6; c = -1

$x = \dfrac{-(-6) \pm \sqrt{(-6)^2 - 4(1)(-1)}}{2(1)}$

$x = \dfrac{6 \pm \sqrt{36 + 4}}{2}$

$x = \dfrac{6 \pm \sqrt{40}}{2}$

$x = \dfrac{6 \pm \sqrt{4 \times 10}}{2}$

$x = \dfrac{6 \pm 2 \sqrt{10}}{2}$

$x = 3 \pm \sqrt{10}$