Solve Using the Quadratic Formula 2x^2-22=0

$2 x^{2} - 22 = 0$

Step 1

Use the quadratic formula to find the solutions.

$\frac{- b \pm \sqrt{b^{2} - 4 (a c)}}{2 a}$

Step 2

Substitute the values $a = 2$ , $b = 0$ , and $c = - 22$ into the quadratic formula and solve for $x$ .

$\frac{0 \pm \sqrt{0^{2} - 4 \cdot (2 \cdot - 22)}}{2 \cdot 2}$

Step 3

Simplify.

Simplify the numerator.

Raising $0$ to any positive power yields $0$ .

$x = \frac{0 \pm \sqrt{0 - 4 \cdot 2 \cdot - 22}}{2 \cdot 2}$

Multiply $- 4 \cdot 2 \cdot - 22$ .

Multiply $- 4$ by $2$ .

$x = \frac{0 \pm \sqrt{0 - 8 \cdot - 22}}{2 \cdot 2}$

Multiply $- 8$ by $- 22$ .

$x = \frac{0 \pm \sqrt{0 + 176}}{2 \cdot 2}$

Add $0$ and $176$ .

$x = \frac{0 \pm \sqrt{176}}{2 \cdot 2}$

Rewrite $176$ as $4^{2} \cdot 11$ .

Factor $16$ out of $176$ .

$x = \frac{0 \pm \sqrt{16 (11)}}{2 \cdot 2}$

Rewrite $16$ as $4^{2}$ .

$x = \frac{0 \pm \sqrt{4^{2} \cdot 11}}{2 \cdot 2}$

Pull terms out from under the radical.

$x = \frac{0 \pm 4 \sqrt{11}}{2 \cdot 2}$

Multiply $2$ by $2$ .

$x = \frac{0 \pm 4 \sqrt{11}}{4}$

Simplify $\frac{0 \pm 4 \sqrt{11}}{4}$ .

$x = \pm \sqrt{11}$

Step 4

The result can be shown in multiple forms.

Exact Form:

$x = \pm \sqrt{11}$

Decimal Form:

$x = 3.31662479 \dots, - 3.31662479 \dots$