# How do you solve 2x^2 + 2x – 1 = 0?

Jul 18, 2018

$x = \frac{- 1 \pm \sqrt{3}}{2}$

#### Explanation:

To solve this, we will use the quadratic formula. We know that this is in standard quadratic form, or $a {x}^{2} + b x + c$, where $a = 2$, $b = 2$, and $c = - 1$.

$x = \frac{- b \pm \sqrt{{b}^{2} - 4 a c}}{2 a}$

Now plug in the values of $a$, $b$, and $c$ into the formula to find the value of $x$:
$x = \frac{- 2 \pm \sqrt{{2}^{2} - 4 \left(2\right) \left(- 1\right)}}{2 \left(2\right)}$

$x = \frac{- 2 \pm \sqrt{4 + 8}}{4}$

$x = \frac{- 2 \pm \sqrt{12}}{4}$

$x = \frac{- 2 \pm 2 \sqrt{3}}{4}$

$x = \frac{- 1 \pm \sqrt{3}}{2}$

Hope this helps!