Solve for x 20+2x^2=28

$20 + 2 x^{2} = 28$

Move all terms not containing $x$ to the right side of the equation.

Subtract $20$ from both sides of the equation.

$2 x^{2} = 28 - 20$

Subtract $20$ from $28$ .

$2 x^{2} = 8$

Divide each term in $2 x^{2} = 8$ by $2$ and simplify.

Divide each term in $2 x^{2} = 8$ by $2$ .

$\frac{2 x^{2}}{2} = \frac{8}{2}$

Simplify the left side.

Cancel the common factor of $2$ .

Cancel the common factor.

$\frac{2 x^{2}}{2} = \frac{8}{2}$

Divide $x^{2}$ by $1$ .

$x^{2} = \frac{8}{2}$

Simplify the right side.

Divide $8$ by $2$ .

$x^{2} = 4$

Take the square root of both sides of the equation to eliminate the exponent on the left side.

$x = \pm \sqrt{4}$

Simplify $\pm \sqrt{4}$ .

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

$x = \pm \sqrt{2^{2}}$

Pull terms out from under the radical, assuming positive real numbers.

$x = \pm 2$

The complete solution is the result of both the positive and negative portions of the solution.

First, use the positive value of the $\pm$ to find the first solution.

$x = 2$

Next, use the negative value of the $\pm$ to find the second solution.

$x = - 2$

The complete solution is the result of both the positive and negative portions of the solution.

$x = 2, - 2$