# Precalculus Examples

, ,

Step 1

When two variable quantities have a constant ratio, their relationship is called a direct variation. It is said that one variable varies directly as the other. The formula for direct variation is , where is the constant of variation.

Step 2

Solve the equation for , the constant of variation.

Step 3

Replace the variables and with the actual values.

Step 4

Step 4.1

Factor out of .

Step 4.2

Cancel the common factors.

Step 4.2.1

Factor out of .

Step 4.2.2

Cancel the common factor.

Step 4.2.3

Rewrite the expression.

Step 5

Use the formula to substitute for and for .

Step 6

Step 6.1

Multiply by .

Step 6.2

Multiply by .

Step 6.3

Remove parentheses.

Step 6.4

Simplify .

Step 6.4.1

Cancel the common factor of .

Step 6.4.1.1

Factor out of .

Step 6.4.1.2

Cancel the common factor.

Step 6.4.1.3

Rewrite the expression.

Step 6.4.2

Multiply by .