Solve Using the Square Root Property 5x^2-105=0

$5 x^{2} - 105 = 0$

Step 1

Add $105$ to both sides of the equation.

$5 x^{2} = 105$

Step 2

Divide each term in $5 x^{2} = 105$ by $5$ and simplify.

Divide each term in $5 x^{2} = 105$ by $5$ .

$\frac{5 x^{2}}{5} = \frac{105}{5}$

Simplify the left side.

Cancel the common factor of $5$ .

Cancel the common factor.

$\frac{5 x^{2}}{5} = \frac{105}{5}$

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

$x^{2} = \frac{105}{5}$

Simplify the right side.

Divide $105$ by $5$ .

$x^{2} = 21$

Step 3

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

$x = \pm \sqrt{21}$

Step 4

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.

$x = \sqrt{21}$

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

$x = - \sqrt{21}$

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

$x = \sqrt{21}, - \sqrt{21}$

Step 5

The result can be shown in multiple forms.

Exact Form:

$x = \sqrt{21}, - \sqrt{21}$

Decimal Form:

$x = 4.58257569 \dots, - 4.58257569 \dots$