Precalculus Examples

$f (3) = \frac{7 x}{3 x - 13}$

Step 1

Replace the variable $x$ with $3$ in the expression.

$f (3) = \frac{7 (3)}{3 (3) - 13}$

Step 2

Simplify the result.

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Step 2.1

Multiply $7$ by $3$ .

$f (3) = \frac{21}{3 (3) - 13}$

Step 2.2

Simplify the denominator.

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Step 2.2.1

Multiply $3$ by $3$ .

$f (3) = \frac{21}{9 - 13}$

Step 2.2.2

Subtract $13$ from $9$ .

$f (3) = \frac{21}{- 4}$

Step 2.3

Move the negative in front of the fraction.

$f (3) = - \frac{21}{4}$

Step 2.4

The final answer is $- \frac{21}{4}$ .

$- \frac{21}{4}$

Step 3

The result can be shown in multiple forms.

Exact Form:

$- \frac{21}{4}$

Decimal Form:

$- 5.25$

Mixed Number Form:

$- 5 \frac{1}{4}$

Step 4