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Warm Up. Problem of the Day. Lesson Presentation. Lesson Quizzes. 1. __. 2. Warm Up Evaluate each expression for the given value of the variable. 1. 4 x – 1 for x = 2 2. 7 y + 3 for y = 5 3. x + 2 for x = –6 4. 8 y – 3 for y = –2. 7. 38. –1. –19. Problem of the Day
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Warm Up Problem of the Day Lesson Presentation Lesson Quizzes
1 __ 2 Warm Up Evaluate each expression for the given value of the variable. 1. 4x – 1 for x = 2 2. 7y + 3 for y = 5 3.x + 2 for x = –6 4. 8y – 3 for y = –2 7 38 –1 –19
Problem of the Day These are rits: 24042, 383, and 4994. These are not rits: 39239, 28, and 5505. Which of these are rits: 39883, 4040, and 101? Why? 101 is a rit because it is the same forward and backward
Learn to use data in a table to write an equation for a function and to use the equation to find a missing value.
Vocabulary function input output
A function is a rule that relates two quantities so that each input value corresponds exactly to one output value.
x 3 4 5 6 7 10 y 13 16 19 22 25 Compare x and y to find a pattern. Use the pattern to write an equation. Substitute 10 for x. Use your function rule to find y when x = 10. Additional Example 1: Writing Equations from Function Tables Write an equation for a function that gives the values in the table. Use the equation to find the value of y for the indicated value of x. y is 3 times x plus 4. y = 3x + 4 y = 3(10) + 4 y = 30 + 4 = 34
Helpful Hint When all the y-values are greater than the corresponding x-values, use addition and/or multiplication in your equation.
x 3 4 5 6 7 10 y 10 12 14 16 18 Compare x and y to find a pattern. Use the pattern to write an equation. Substitute 10 for x. Use your function rule to find y when x = 10. Check It Out: Example 1 Write an equation for a function that gives the values in the table. Use the equation to find the value of y for the indicated value of x. y is 2 times x + 4. y = 2x + 4 y = 2(10) + 4 y = 20 + 4 = 24
You can write equations for functions that are described in words.
Choose variables for the equation. Write an equation. Additional Example 2: Translating Words into Math Write an equation for the function. Tell what each variable you use represents. The height of a painting is 7 times its width. h = height of painting w = width of painting h = 7w
Choose variables for the equation. Write an equation. Check It Out: Example 2 Write an equation for the function. Tell what each variable you use represents. The height of a mirror is 4 times its width. h = height of mirror w = width of mirror h = 4w
1 Understand the Problem Additional Example 3: Problem Solving Application The school choir tracked the number of tickets sold and the total amount of money received. They sold each ticket for the same price. They received $80 for 20 tickets, $88 for 22 tickets, and $108 for 27 tickets. Write an equation for the function. The answer will be an equation that describes the relationship between the number of tickets sold and the money received.
2 Make a Plan 3 Solve t 20 22 27 m 80 88 108 Compare t and m. Write an equation. You can make a table to display the data. Let t be the number of tickets. Let m be the amount of money received. m is equal to 4 times t. m = 4t
4 Look Back ? ? ? 80= 4•20 88= 4•22 108= 4•27 ? ? ? 80= 80 88= 88 108= 108 Substitute the t and m values in the table to check that they are solutions of the equation m = 4t. m = 4t (20, 80) m = 4t (22, 88) m = 4t (27, 108)
1 Understand the Problem Check It Out: Example 3 The school theater tracked the number of tickets sold and the total amount of money received. They sold each ticket for the same price. They received $45 for 15 tickets, $63 for 21 tickets, and $90 for 30 tickets. Write an equation for the function. The answer will be an equation that describes the relationship between the number of tickets sold and the money received.
2 Make a Plan 3 Solve t 15 21 30 m 45 63 90 Compare t and m. Write an equation. You can make a table to display the data. Let t be the number of tickets. Let m be the amount of money received. m is equal to 3 times t. m = 3t
4 Look Back ? ? ? 45= 3•15 63 = 3•21 90= 3•30 ? ? ? 45= 45 63= 63 90= 90 Substitute the t and m values in the table to check that they are solutions of the equation m = 3t. m = 3t (15, 45) m = 3t (21, 63) m = 3t (30, 90)
Lesson Quizzes Standard Lesson Quiz Lesson Quiz for Student Response Systems
x 0 1 3 5 7 y 0 3 9 15 Lesson Quiz 1. Write an equation for a function that gives the values in the table below. Use the equation to find the value for y for the indicated value of x. 2. Write an equation for the function. Tell what each variable you use represents. The height of a round can is 2 times its radius. y = 3x; 21 h = 2r, where h is the height and r is the radius
Lesson Quiz for Student Response Systems 1. Identify an equation for a function that gives the values in the table below. Then, use the equation to find the value for y for the indicated value of x. A. y = 4x + 8; 21 B. y = 7x – 7; 21 C. y = 4x + 8; 28 D. y = 7x – 7; 28
Lesson Quiz for Student Response Systems 2. Identify an equation for the function. Tell what each variable you use represents. The width of a swimming pool is twice its depth. A. w = 2d, where d is the width and w is the depth B. , where w is the width and d is the depth C. w = 2d, where w is the width and d is the depth D. , where d is the width and w is the depth