Find the Domain (x+4)^2+(y+2)^2=9

${(x + 4)}^{2} + {(y + 2)}^{2} = 9$

Step 1

Subtract ${(x + 4)}^{2}$ from both sides of the equation.

${(y + 2)}^{2} = 9 - {(x + 4)}^{2}$

Step 2

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

$y + 2 = \pm \sqrt{9 - {(x + 4)}^{2}}$

Step 3

Simplify $\pm \sqrt{9 - {(x + 4)}^{2}}$ .

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

$y + 2 = \pm \sqrt{3^{2} - {(x + 4)}^{2}}$

Since both terms are perfect squares, factor using the difference of squares formula, $a^{2} - b^{2} = (a + b) (a - b)$ where $a = 3$ and $b = x + 4$ .

$y + 2 = \pm \sqrt{(3 + x + 4) (3 - (x + 4))}$

Simplify.

Add $3$ and $4$ .

$y + 2 = \pm \sqrt{(x + 7) (3 - (x + 4))}$

Apply the distributive property.

$y + 2 = \pm \sqrt{(x + 7) (3 - x - 1 \cdot 4)}$

Multiply $- 1$ by $4$ .

$y + 2 = \pm \sqrt{(x + 7) (3 - x - 4)}$

Subtract $4$ from $3$ .

$y + 2 = \pm \sqrt{(x + 7) (- x - 1)}$

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.

$y + 2 = \sqrt{(x + 7) (- x - 1)}$

Subtract $2$ from both sides of the equation.

$y = \sqrt{(x + 7) (- x - 1)} - 2$

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

$y + 2 = - \sqrt{(x + 7) (- x - 1)}$

Subtract $2$ from both sides of the equation.

$y = - \sqrt{(x + 7) (- x - 1)} - 2$

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

$y = \sqrt{(x + 7) (- x - 1)} - 2$

$y = - \sqrt{(x + 7) (- x - 1)} - 2$

$y = \sqrt{(x + 7) (- x - 1)} - 2$

$y = - \sqrt{(x + 7) (- x - 1)} - 2$

Step 5

Set the radicand in $\sqrt{(x + 7) (- x - 1)}$ greater than or equal to $0$ to find where the expression is defined.

$(x + 7) (- x - 1) \geq 0$

Step 6

Solve for $x$ .

If any individual factor on the left side of the equation is equal to $0$ , the entire expression will be equal to $0$ .

$x + 7 = 0$

$- x - 1 = 0$

Set $x + 7$ equal to $0$ and solve for $x$ .

Set $x + 7$ equal to $0$ .

$x + 7 = 0$

Subtract $7$ from both sides of the equation.

$x = - 7$

Set $- x - 1$ equal to $0$ and solve for $x$ .

Set $- x - 1$ equal to $0$ .

$- x - 1 = 0$

Solve $- x - 1 = 0$ for $x$ .

Add $1$ to both sides of the equation.

$- x = 1$

Divide each term in $- x = 1$ by $- 1$ and simplify.

Divide each term in $- x = 1$ by $- 1$ .

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

Simplify the left side.

Dividing two negative values results in a positive value.

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

Divide $x$ by $1$ .

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

Simplify the right side.

Divide $1$ by $- 1$ .

$x = - 1$

The final solution is all the values that make $(x + 7) (- x - 1) \geq 0$ true.

$x = - 7, - 1$

Use each root to create test intervals.

$x < - 7$

$- 7 < x < - 1$

$x > - 1$

Choose a test value from each interval and plug this value into the original inequality to determine which intervals satisfy the inequality.

Test a value on the interval $x < - 7$ to see if it makes the inequality true.

Choose a value on the interval $x < - 7$ and see if this value makes the original inequality true.

$x = - 10$

Replace $x$ with $- 10$ in the original inequality.

$((- 10) + 7) (- (- 10) - 1) \geq 0$

The left side $- 27$ is less than the right side $0$ , which means that the given statement is false.

False

Test a value on the interval $- 7 < x < - 1$ to see if it makes the inequality true.

Choose a value on the interval $- 7 < x < - 1$ and see if this value makes the original inequality true.

$x = - 4$

Replace $x$ with $- 4$ in the original inequality.

$((- 4) + 7) (- (- 4) - 1) \geq 0$

The left side $9$ is greater than the right side $0$ , which means that the given statement is always true.

True

Test a value on the interval $x > - 1$ to see if it makes the inequality true.

Choose a value on the interval $x > - 1$ and see if this value makes the original inequality true.

$x = 0$

Replace $x$ with $0$ in the original inequality.

$((0) + 7) (- (0) - 1) \geq 0$

The left side $- 7$ is less than the right side $0$ , which means that the given statement is false.

False

Compare the intervals to determine which ones satisfy the original inequality.

$x < - 7$ False

$- 7 < x < - 1$ True

$x > - 1$ False

$x < - 7$ False

$- 7 < x < - 1$ True

$x > - 1$ False

The solution consists of all of the true intervals.

$- 7 \leq x \leq - 1$

Step 7

The domain is all values of $x$ that make the expression defined.

Interval Notation:

$[- 7, - 1]$

Set-Builder Notation:

${x | - 7 \leq x \leq - 1}$

Step 8

Find the Domain (x+4)^2+(y+2)^2=9

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