1. Example 3 Solving an Equation Using Addition The solution is 17.5. ANSWER Original equation 13=4.5c– Add 4.5 to each side. (Addition property of equality) 13=4.5c–+ + Substitute 17.5 for c in original equation. CHECK 13– = ? 17.54.5 Solution checks. 13 = Simplify. 17.5c=

2. ROCK CLIMBING You have about 825 feet left to climb. ANSWER Example 4 Using a Model A cliff has a height of about 1500 feet. If you have already climbed 675 feet, how much farther do you have to climb to reach the top? SOLUTION Let x represent the distance left to climb. Write an algebraic model. x= 1500+ 675 Subtract 675 from each side. 6751500–x=+ 675 – Simplify. 825x=

3. ANSWER 8.4 ANSWER 113 seashells Solve the equation10. =26.4.z– Check your solution. 11. SEASHELLS Lucinda combines her 49 seashells with Jerry’s seashells, for a total of 162. How many seashells did Jerry have? Guided Practice for Examples 3 and 4