Chapter 9: Problem 21

Determine whether each equation represents direct, inverse, joint, or combined variation. $$y=\frac{78}{x}$$

### Short Answer

## Step by step solution

## Identify the given equation

## Compare with the standard forms of variations

## Match the given equation to the standard forms

## Conclusion

## Key Concepts

These are the key concepts you need to understand to accurately answer the question.

###### Direct Variation

Here,

**y**and**x**are the variables.**k**is the constant of variation.

###### Joint Variation

\(y = kxz \)

Here,

**y**is the variable that varies.**x**and**z**are the variables that affect**y**.**k**is the constant of variation.

###### Combined Variation

\(y = k \frac{x}{z} \ln(w)\).

In this case -

- \(y\): Variable of interest
- \(x\): Directly proportional variable
- \(z\): Inversely proportional variable
- \(w\): Another variable affecting \(y\)
- \(k\): Constant of variation