Precalculus Examples

$f (x) = - 3 x^{2} - 7 x$ Find $f (7)$

Step 1

Replace the variable $x$ with $7$ in the expression.

$f (7) = - 3 {(7)}^{2} - 7 \cdot 7$

Step 2

Simplify $- 3 {(7)}^{2} - 7 \cdot 7$ .

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Step 2.1

Remove parentheses.

$- 3 {(7)}^{2} - 7 \cdot 7$

Step 2.2

Simplify each term.

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Step 2.2.1

Raise $7$ to the power of $2$ .

$- 3 \cdot 49 - 7 \cdot 7$

Step 2.2.2

Multiply $- 3$ by $49$ .

$- 147 - 7 \cdot 7$

Step 2.2.3

Multiply $- 7$ by $7$ .

$- 147 - 49$

Step 2.3

Subtract $49$ from $- 147$ .

$- 196$