2. Transparency 5 Click the mouse button or press the Space Bar to display the answers.

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4. Example 5-1b Objective Solve equations using mental math

5. Example 5-1b Vocabulary Equation A sentence in math that contains an equal sign

6. Example 5-1b Vocabulary Solution A number that makes the equation true

7. Example 5-1b Vocabulary Solving an equation The process of finding a solution

8. Example 5-1b Vocabulary Defining the variable To choose a variable to represent one of the unknowns

9. Example 5-1b Math Symbols = is equal to ≠is not equal to

10. Lesson 5 Contents Example 1Solve an Equation Mentally Example 2Graph the Solution of an Equation Example 3Write an Equation to Solve a Problem Example 4Find a Solution of an Equation

11. Example 5-1a Solve mentally 1/4 THINK What number divided by 2 equals 3? Replace x with 6 6 Write equation Just because it says “mentally” there is still work to do You know that 2  3 = 6, so try 6 as your solution

12. Example 5-1b 1/4 Solve mentally 6 Divide 6 by 2 3 Bring down = 3 3 = 3 This is a true statement so 3 is the solution Answer: The solution is 3

13. Example 5-1b Solve mentally. Answer: 17 1/4

14. Example 5-2a Graph the solution of the equation 2/4 Write equation Remember: You solved this equation in example 2 and the solution was 6 Draw a number line that includes the solution

15. Example 5-2a Graph the solution of the equation 2/4 Answer: Plot 6 on the number line

16. Example 5-2b Answer: Graph the solution of the equation 2/4

17. Example 5-3a ENTERTAINMENT An adult paid $18.50 for herself and two students to see a movie. If the two student tickets cost $11 together, what is the cost of the adult ticket? Words Variable The cost of one adult ticket plus two student tickets is $18.50. Let a represent the cost of an adult movie ticket. 3/4 Two student tickets cost $11 Total cost is $18.50 Write Equation a + 11 = 18.50

18. Example 5-3a ENTERTAINMENT An adult paid $18.50 for herself and two students to see a movie. If the two student tickets cost $11 together, what is the cost of the adult ticket? Solve equation mentally 3/4 a + 11 = 18.50 THINK What number added to 11 = 18.50 Replace a with 7.50 7.50 + 11 = 18.50 You know that 18.50 - 11 is 7.50, so try 7.50 as your solution

19. Example 5-3a ENTERTAINMENT An adult paid $18.50 for herself and two students to see a movie. If the two student tickets cost $11 together, what is the cost of the adult ticket? Add 7.50 + 11 3/4 7.50 + 11 = 18.50 18.5018.50 = 18.50 Answer: The cost of an adult movie ticket is $7.50. Bring down = 18.50 This is a true statement so 7.50 is the solution

20. Example 5-3c ICE CREAM Julie spends $9.50 at the ice cream parlor. She buys a hot fudge sundae for herself and ice cream cones for each of the three friends who are with her. Find the cost of Julie’s sundae if the three ice cream cones together cost $6.30. Answer: $3.20 3/4

21. Example 5-4c 4/4 MULTIPLE- CHOICE TEST ITEM What value of x is a solution of A 5 B 6 C 7 D 8 Write equation 12 - x = 5 THINK What number subtracted from 12 equals 5 You know that 12 - 5 is 7, so try 7 as your solution Replace x with 7 12 - 7 = 5

22. Example 5-4c 4/4 MULTIPLE- CHOICE TEST ITEM What value of x is a solution of A 5 B 6 C 7 D 8 Subtract 7 from 12 12 - 7 = 5 Bring down = 5 This is a true statement so 7 is the solution Choose the correct multiple choice letter 55 = 5 Answer: C

23. Example 5-4c What value of x is a solution of MULTIPLE- CHOICE TEST ITEM A 34 B 35 C 36 D 9 Answer: B * 4/4

24. End of Lesson 5 Assignment Lesson 1:5Algebra: Equations14 - 35 All