Precalculus Examples

$y = x^{3} - 8$

Step 1

Find the point at $x = - 2$ .

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Step 1.1

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

$f (- 2) = {(- 2)}^{3} - 8$

Step 1.2

Simplify the result.

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Step 1.2.1

Raise $- 2$ to the power of $3$ .

$f (- 2) = - 8 - 8$

Step 1.2.2

Subtract $8$ from $- 8$ .

$f (- 2) = - 16$

Step 1.2.3

The final answer is $- 16$ .

$- 16$

Step 1.3

Convert $- 16$ to decimal.

$y = - 16$

Step 2

Find the point at $x = - 1$ .

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Step 2.1

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

$f (- 1) = {(- 1)}^{3} - 8$

Step 2.2

Simplify the result.

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Step 2.2.1

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

$f (- 1) = - 1 - 8$

Step 2.2.2

Subtract $8$ from $- 1$ .

$f (- 1) = - 9$

Step 2.2.3

The final answer is $- 9$ .

$- 9$

Step 2.3

Convert $- 9$ to decimal.

$y = - 9$

Step 3

Find the point at $x = 0$ .

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Step 3.1

Replace the variable $x$ with $0$ in the expression.

$f (0) = {(0)}^{3} - 8$

Step 3.2

Simplify the result.

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Step 3.2.1

Raising $0$ to any positive power yields $0$ .

$f (0) = 0 - 8$

Step 3.2.2

Subtract $8$ from $0$ .

$f (0) = - 8$

Step 3.2.3

The final answer is $- 8$ .

$- 8$

Step 3.3

Convert $- 8$ to decimal.

$y = - 8$

Step 4

Find the point at $x = 1$ .

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Step 4.1

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

$f (1) = {(1)}^{3} - 8$

Step 4.2

Simplify the result.

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Step 4.2.1

One to any power is one.

$f (1) = 1 - 8$

Step 4.2.2

Subtract $8$ from $1$ .

$f (1) = - 7$

Step 4.2.3

The final answer is $- 7$ .

$- 7$

Step 4.3

Convert $- 7$ to decimal.

$y = - 7$

Step 5

Find the point at $x = 2$ .

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Step 5.1

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

$f (2) = {(2)}^{3} - 8$

Step 5.2

Simplify the result.

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Step 5.2.1

Raise $2$ to the power of $3$ .

$f (2) = 8 - 8$

Step 5.2.2

Subtract $8$ from $8$ .

$f (2) = 0$

Step 5.2.3

The final answer is $0$ .

$0$

Step 5.3

Convert $0$ to decimal.

$y = 0$

Step 6

The cubic function can be graphed using the function behavior and the points.

$\begin{array}{c} x & y \\ - 2 & - 16 \\ - 1 & - 9 \\ 0 & - 8 \\ 1 & - 7 \\ 2 & 0 \end{array}$

Step 7

The cubic function can be graphed using the function behavior and the selected points.

Falls to the left and rises to the right

$\begin{array}{c} x & y \\ - 2 & - 16 \\ - 1 & - 9 \\ 0 & - 8 \\ 1 & - 7 \\ 2 & 0 \end{array}$

Step 8