Solve for x log base x of 9=-2

$\log_{x} (9) = - 2$

Step 1

Rewrite $\log_{x} (9) = - 2$ in exponential form using the definition of a logarithm. If $x$ and $b$ are positive real numbers and $b \neq 1$ , then $\log_{b} (x) = y$ is equivalent to $b^{y} = x$ .

$x^{- 2} = 9$

Step 2

Solve for $x$ .

Rewrite the expression using the negative exponent rule $b^{- n} = \frac{1}{b^{n}}$ .

$\frac{1}{x^{2}} = 9$

Find the LCD of the terms in the equation.

Finding the LCD of a list of values is the same as finding the LCM of the denominators of those values.

$x^{2}, 1$

The LCM of one and any expression is the expression.

$x^{2}$

Multiply each term in $\frac{1}{x^{2}} = 9$ by $x^{2}$ to eliminate the fractions.

Multiply each term in $\frac{1}{x^{2}} = 9$ by $x^{2}$ .

$\frac{1}{x^{2}} x^{2} = 9 x^{2}$

Simplify the left side.

Cancel the common factor of $x^{2}$ .

Cancel the common factor.

$\frac{1}{x^{2}} x^{2} = 9 x^{2}$

Rewrite the expression.

$1 = 9 x^{2}$

Solve the equation.

Rewrite the equation as $9 x^{2} = 1$ .

$9 x^{2} = 1$

Divide each term in $9 x^{2} = 1$ by $9$ and simplify.

Divide each term in $9 x^{2} = 1$ by $9$ .

$\frac{9 x^{2}}{9} = \frac{1}{9}$

Simplify the left side.

Cancel the common factor of $9$ .

Cancel the common factor.

$\frac{9 x^{2}}{9} = \frac{1}{9}$

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

$x^{2} = \frac{1}{9}$

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

$x = \pm \sqrt{\frac{1}{9}}$

Simplify $\pm \sqrt{\frac{1}{9}}$ .

Rewrite $\sqrt{\frac{1}{9}}$ as $\frac{\sqrt{1}}{\sqrt{9}}$ .

$x = \pm \frac{\sqrt{1}}{\sqrt{9}}$

Any root of $1$ is $1$ .

$x = \pm \frac{1}{\sqrt{9}}$

Simplify the denominator.

Rewrite $9$ as $3^{2}$ .

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

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

$x = \pm \frac{1}{3}$

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.

$x = \frac{1}{3}$

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

$x = - \frac{1}{3}$

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

$x = \frac{1}{3}, - \frac{1}{3}$

Step 3

Exclude the solutions that do not make $\log_{x} (9) = - 2$ true.

$x = \frac{1}{3}$

Step 4

The result can be shown in multiple forms.

Exact Form:

$x = \frac{1}{3}$

Decimal Form:

$x = 0.\overline{3}$

Solve for x log base x of 9=-2

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