Precalculus Examples

$f (x) = 4 x^{2} + 6 x - 2$ Find $f (- 5)$

Step 1

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

$f (- 5) = 4 {(- 5)}^{2} + 6 (- 5) - 2$

Step 2

Simplify $4 {(- 5)}^{2} + 6 (- 5) - 2$ .

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Step 2.1

Remove parentheses.

$4 {(- 5)}^{2} + 6 (- 5) - 2$

Step 2.2

Simplify each term.

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Step 2.2.1

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

$4 \cdot 25 + 6 (- 5) - 2$

Step 2.2.2

Multiply $4$ by $25$ .

$100 + 6 (- 5) - 2$

Step 2.2.3

Multiply $6$ by $- 5$ .

$100 - 30 - 2$

Step 2.3

Simplify by subtracting numbers.

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Step 2.3.1

Subtract $30$ from $100$ .

$70 - 2$

Step 2.3.2

Subtract $2$ from $70$ .

$68$