Graph g(x)=-(x+3)^2-5

$g (x) = - {(x + 3)}^{2} - 5$

Step 1

Find the properties of the given parabola.

Use the vertex form, $y = a {(x - h)}^{2} + k$ , to determine the values of $a$ , $h$ , and $k$ .

$a = - 1$

$h = - 3$

$k = - 5$

Since the value of $a$ is negative, the parabola opens down.

Opens Down

Find the vertex $(h, k)$ .

$(- 3, - 5)$

Find $p$ , the distance from the vertex to the focus.

Find the distance from the vertex to a focus of the parabola by using the following formula.

$\frac{1}{4 a}$

Substitute the value of $a$ into the formula.

$\frac{1}{4 \cdot - 1}$

Cancel the common factor of $1$ and $- 1$ .

Rewrite $1$ as $- 1 (- 1)$ .

$\frac{- 1 (- 1)}{4 \cdot - 1}$

Move the negative in front of the fraction.

$- \frac{1}{4}$

Find the focus.

The focus of a parabola can be found by adding $p$ to the y-coordinate $k$ if the parabola opens up or down.

$(h, k + p)$

Substitute the known values of $h$ , $p$ , and $k$ into the formula and simplify.

$(- 3, - \frac{21}{4})$

Find the axis of symmetry by finding the line that passes through the vertex and the focus.

$x = - 3$

Find the directrix.

The directrix of a parabola is the horizontal line found by subtracting $p$ from the y-coordinate $k$ of the vertex if the parabola opens up or down.

$y = k - p$

Substitute the known values of $p$ and $k$ into the formula and simplify.

$y = - \frac{19}{4}$

Use the properties of the parabola to analyze and graph the parabola.

Direction: Opens Down

Vertex: $(- 3, - 5)$

Focus: $(- 3, - \frac{21}{4})$

Axis of Symmetry: $x = - 3$

Directrix: $y = - \frac{19}{4}$

Direction: Opens Down

Vertex: $(- 3, - 5)$

Focus: $(- 3, - \frac{21}{4})$

Axis of Symmetry: $x = - 3$

Directrix: $y = - \frac{19}{4}$

Step 2

Select a few $x$ values, and plug them into the equation to find the corresponding $y$ values. The $x$ values should be selected around the vertex.

Replace the variable $x$ with $- 4$ in the expression.

$f (- 4) = - {(- 4)}^{2} - 6 \cdot - 4 - 14$

Simplify the result.

Simplify each term.

Raise $- 4$ to the power of $2$ .

$f (- 4) = - 1 \cdot 16 - 6 \cdot - 4 - 14$

Multiply $- 1$ by $16$ .

$f (- 4) = - 16 - 6 \cdot - 4 - 14$

Multiply $- 6$ by $- 4$ .

$f (- 4) = - 16 + 24 - 14$

Simplify by adding and subtracting.

Add $- 16$ and $24$ .

$f (- 4) = 8 - 14$

Subtract $14$ from $8$ .

$f (- 4) = - 6$

The final answer is $- 6$ .

$- 6$

The $y$ value at $x = - 4$ is $- 6$ .

$y = - 6$

Replace the variable $x$ with $- 5$ in the expression.

$f (- 5) = - {(- 5)}^{2} - 6 \cdot - 5 - 14$

Simplify the result.

Simplify each term.

Raise $- 5$ to the power of $2$ .

$f (- 5) = - 1 \cdot 25 - 6 \cdot - 5 - 14$

Multiply $- 1$ by $25$ .

$f (- 5) = - 25 - 6 \cdot - 5 - 14$

Multiply $- 6$ by $- 5$ .

$f (- 5) = - 25 + 30 - 14$

Simplify by adding and subtracting.

Add $- 25$ and $30$ .

$f (- 5) = 5 - 14$

Subtract $14$ from $5$ .

$f (- 5) = - 9$

The final answer is $- 9$ .

$- 9$

The $y$ value at $x = - 5$ is $- 9$ .

$y = - 9$

Replace the variable $x$ with $- 2$ in the expression.

$f (- 2) = - {(- 2)}^{2} - 6 \cdot - 2 - 14$

Simplify the result.

Simplify each term.

Raise $- 2$ to the power of $2$ .

$f (- 2) = - 1 \cdot 4 - 6 \cdot - 2 - 14$

Multiply $- 1$ by $4$ .

$f (- 2) = - 4 - 6 \cdot - 2 - 14$

Multiply $- 6$ by $- 2$ .

$f (- 2) = - 4 + 12 - 14$

Simplify by adding and subtracting.

Add $- 4$ and $12$ .

$f (- 2) = 8 - 14$

Subtract $14$ from $8$ .

$f (- 2) = - 6$

The final answer is $- 6$ .

$- 6$

The $y$ value at $x = - 2$ is $- 6$ .

$y = - 6$

Replace the variable $x$ with $- 1$ in the expression.

$f (- 1) = - {(- 1)}^{2} - 6 \cdot - 1 - 14$

Simplify the result.

Simplify each term.

Multiply $- 1$ by ${(- 1)}^{2}$ by adding the exponents.

Multiply $- 1$ by ${(- 1)}^{2}$ .

Raise $- 1$ to the power of $1$ .

$f (- 1) = (- 1) {(- 1)}^{2} - 6 \cdot - 1 - 14$

Use the power rule $a^{m} a^{n} = a^{m + n}$ to combine exponents.

$f (- 1) = {(- 1)}^{1 + 2} - 6 \cdot - 1 - 14$

Add $1$ and $2$ .

$f (- 1) = {(- 1)}^{3} - 6 \cdot - 1 - 14$

Raise $- 1$ to the power of $3$ .

$f (- 1) = - 1 - 6 \cdot - 1 - 14$

Multiply $- 6$ by $- 1$ .

$f (- 1) = - 1 + 6 - 14$

Simplify by adding and subtracting.

Add $- 1$ and $6$ .

$f (- 1) = 5 - 14$

Subtract $14$ from $5$ .

$f (- 1) = - 9$

The final answer is $- 9$ .

$- 9$

The $y$ value at $x = - 1$ is $- 9$ .

$y = - 9$

Graph the parabola using its properties and the selected points.

$\begin{array}{c} x & y \\ - 5 & - 9 \\ - 4 & - 6 \\ - 3 & - 5 \\ - 2 & - 6 \\ - 1 & - 9 \end{array}$

Step 3

Graph the parabola using its properties and the selected points.

Direction: Opens Down

Vertex: $(- 3, - 5)$

Focus: $(- 3, - \frac{21}{4})$

Axis of Symmetry: $x = - 3$

Directrix: $y = - \frac{19}{4}$

$\begin{array}{c} x & y \\ - 5 & - 9 \\ - 4 & - 6 \\ - 3 & - 5 \\ - 2 & - 6 \\ - 1 & - 9 \end{array}$

Step 4

Graph g(x)=-(x+3)^2-5

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