Warm Up Problem of the Day Lesson Presentation Lesson Quizzes

Warm Up Add or subtract. 7 10 5 10 1 5 1. + 3 8 5 16 1 16 2. 2 – 1 3. 4.8 + 3.6 8.4 4. 2.4 – 0.05 2.35

Problem of the Day A computer word is made of strings of 0’s and 1’s. How many different words can be formed using 3 characters? (An example is 010.)‏ 8

Learn to solve equations with rational numbers.

Additional Examples 1A: Solving Equations with Decimals Solve. m + 4.6 = 9 Use the Subtraction Property of Equality. Subtract 4.6 from both sides. m + 4.6 = 9 – 4.6 = 4.4 m = Once you have solved an equation it is a good idea to check your answer. To check your answer, substitute your answer for the variable in the original equation. Remember!

Additional Examples 1B: Solving Equations with Decimals Solve. 8.2p = –32.8 –32.8 8.2 8.2p 8.2 = Use the Division Property of Equality. Divide both sides by 8.2 –4 p =

Additional Examples 1C: Solving Equations with Decimals Solve. = 15 x 1.2 x 1.2 = 1.2 • 15 1.2 • Use the Multiplication Property of Equality. Multiply both sides by 1.2 x = 18

Check It Out: Example 1A & 1B Solve. A. m + 9.1 = 3 Use the Subtraction Property of Equality. Subtract 9.1 from both sides. m + 9.1 = 3 –9.1 = –6.1 m = B. 5.5b = 75.9 Use the Division Property of Equality. Divide both sides by 5.5 75.9 5.5 5.5 5.5 = b 13.8 b =

C. Solve. Check It Out: Example 1C y 4.5 = 90 Use the Multiplication Property of Equality. Multiply both sides by 4.5 y 4.5 = 4.5 • 90 4.5 • y = 405

Additional Example 2A: Solving Equations with Fractions Solve. 2 7 3 7 n + = – n – + = – – 2 7 3 7 2 7 Subtract from both sides. 2 7 n = – 5 7

Additional Example 2B: Solving Equations with Fractions Solve. 1 6 2 3 y – = 1 6 = 2 3 – + y Add to both sides. 1 6 = y 4 6 1 6 + Find a common denominator; 6. y = 5 6 Simplify.

Additional Example 2C: Solving Equations with Fractions Solve. 5 6 5 8 x = 3 5 6 = 5 8 x 6 5 • Multiply both sides by . 6 5 4 x = 3 4 Simplify.

Solve. Check It Out: Example 2A 1 9 5 9 n + = – 1 9 5 9 n + = – Subtract from both sides. 1 9 n – + = – – 1 9 5 9 1 9 n = – 2 3 Simplify – . 6 9

Solve. Check It Out: Example 2B 1 2 3 4 y – = 1 2 = 3 4 – + y 1 2 3 4 y – = 1 2 = 3 4 – + y Add to both sides. 1 2 = y 3 4 2 4 + Find a common denominator; 4. y = 1 1 4 Simplify.

Solve. Check It Out: Example 2C 3 8 = 6 19 x 2 3 8 = 6 19 x 8 3 • 3 8 = 6 19 x 2 3 8 = 6 19 x 8 3 • Multiply both sides by . 8 3 1 x = 16 19 Simplify.

= 2 Additional Example 3: Solving Word Problems Using Equations Mr. Rios wants to prepare a dessert, but only has 2 tablespoons of sugar. If each serving of the dessert has tablespoon of sugar, how many servings can he make for the party? 2 3 Write an equation: Amount needed for each dessert Amount of sugar Total servings  = s 2 3  = 2

Additional Example 3 Continued Now solve the equation. 2 3  = 2 s 2 3 = 2  s   3 2 Multiply both sides by . 3 2 8 3 s =  3 2 24 6 , or 4 s = Simplify. Mr. Rios can make 4 servings.

Ratio of car’s tank to van’s tank Check It Out: Example 3 Rick’s car holds the amount of gasoline as his wife’s van. If the car’s gas tank can hold gallons of gasoline, how much gasoline can the tank in the minivan hold? 2 3 2 31 Write an equation: Van’s gas tank Ratio of car’s tank to van’s tank Capacity of car’s tank • = 2 3 31 2 g • =

Check It Out: Example 3 Continued Now solve the equation. 2 3 31 2 g • = Multiply both sides by . 3 2 31 2 2 3 = g • 3 2 g = 93 4 Simplify. 1 4 g = 23 The van’s gas tank holds 23 gallons of gasoline. 1 4

Lesson Quizzes Standard Lesson Quiz Lesson Quiz for Student Response Systems

Lesson Quiz: Part I Solve. 1. x – 23.3 = 17.8 x = 41.1 2 3 3 4 j = –15 5 12 2. j + = –14 3 5 1 15 y = 3. 9y = d 3 8 1 2 d = 9 4. = 2 4

Lesson Quiz: Part II 2 5 5. Tamara can mow acre in one hour. If her yard is 2 acres, how many hours will it take her to mow the entire yard? 5 hours

Lesson Quiz for Student Response Systems 1. Solve. a – 36 = 44.9 A. a = 36.7 B. a = 49.2 C. a = 59.9 D. a = 80.9

Lesson Quiz for Student Response Systems 2. Solve. c + = –11 A. c = 12 C. c = 11 B. c = –12 D. c = 11 3 4 4 5 11 20 4 5 11 20 3 4

Lesson Quiz for Student Response Systems 3. Solve. 8e = A. e = 8 C. e = B. e = 5 D. e = 2 3 2 3 1 12 1 3 3 20

Lesson Quiz for Student Response Systems 4. Solve. = 3 A. h = 9 C. h = 11 B. h = 10 D. h = 12 h 3 5 6 1 2 1 2 1 2 1 2