# Equations With Variables on Both Sides

## Lesson Preview

### What You'll Learn

- To solve equations with variables on both sides
- To identify equations that are identities or have no solution

### … And Why

To solve a problem involving renting in-line skates, as in Example 2

Investigation Click here to view the Investigation for this lesson.

## Solving Equations With Variables on Both Sides

To solve an equation that has variables on both sides, use the Addition or Subtraction Properties of Equality to get the variables on one side of the equation.

##### Need Help?

Vertical angles are congruent, so their measures are equal.

#### Real-World Connection

RecreationYou can buy used in-line skates from your friend for $40, or you can rent some. Either way, you must rent safety equipment. How many hours must you skate for the cost of renting and buying skates to be the same?