Lesson 3.4- Solving Multi-Step Equations, pg. 142

Objectives:To solve problems by working backward.To solve equations involving more than one operation.

Vocabulary Multi-Step Equations: equations with more than

one operation.

Consecutive Integers: integers in counting order.

Consecutive integers: 7, 8, 9,… Consecutive odd integers: 5, 7, 9, 11.. Consecutive even integers: 10, 12, 14, 16…

Number theory: the study of numbers and the relationships between them.

Ex. 1: Solve each problem by working backwards.

1. A number multiplied by seven, and then the product is added to 13. The result is 55. What is the number?

2. The English alphabet contains 2 more than twice as many letters as the Hawaiian alphabet. How many letters are there in the Hawaiian alphabet?

3. Nine is subtracted from a number, and then the difference is multiplied by 5. The result is 75. What is the number?

Steps for Solving Multi-Step Equations

Step 1: Undo addition and subtraction

Step 2: Undo multiplication and division.

Step 3: Check

Ex. 2: Solve each equation.

1. 5q – 13 = 37 2. s

129 11

3. 4. 0.2n + 3 = 8.6r

8

32

5. 3.1y – 1.5 = 5.32 6. 18 = 5p + 3

Ex. 3: Write an equation and solve each problem.

1. Twelve decreased by twice a number equals -34. Find the number.

2. Find three consecutive integers whose sum is 42.

3. Find three consecutive even integers whose sum is -30.

Summary

Steps for Solving Multi-Step Equations Step 1: Undo addition or subtraction. Step 2: Undo multiplication or division. Step 3: Check.

Consecutive integers: n, n+1, n+2,… Consecutive odd integers: n, n+2, n+4,… Consecutive even integers: n, n+2, n+4,…

NBA #18, pg. 146, problems 16-46 even