1-6 Variables and Algebraic Expressions Warm Up Evaluate. 1. 5(7) – (18 – 11)  (40 – 35) (12 – 4)

1-6 Variables and Algebraic Expressions Learning Target 3 I can evaluate an algebraic expression.

1-6 Variables and Algebraic Expressions Vocabulary variable constant coefficient algebraic expression evaluate substitute

1-6 Variables and Algebraic Expressions Harrison Ford was born in You can find out what year Harrison turned 18 by adding the year he was born to his age In algebra, letters are often used to represent numbers. You can use a letter such as a to represent Harrison Ford’s age. When he turns a years old, the year will be a.

1-6 Variables and Algebraic Expressions The letter a has a value that can change, or vary. When a letter represents a number that can vary, it is called a variable. The year 1954 is a constant because the number cannot change. An algebraic expression consists of one or more variables. It usually contains constants and operations. For example, a is an algebraic expression for the year Ron Howard turns a certain age.

1-6 Variables and Algebraic Expressions Examples: write an algebraic expression for each word phrase: 1) The product of 5 and a number. 2) The sum of a number and 10 3) 3 less than twice a number 4) 5 less than a number

1-6 Variables and Algebraic Expressions To evaluate an algebraic expression, substitute a number for the variable. AgeYear born + age = year at age a a

1-6 Variables and Algebraic Expressions Evaluate k + 9 for each value of k. Additional Example 1: Evaluating Algebraic Expressions A. k = 5 k Substitute 5 for k. Add. B. k = 2 k Substitute 2 for k. 11 Add.

1-6 Variables and Algebraic Expressions Additional Example 2: Evaluating Algebraic Expressions Involving Order of Operations B. s ÷ 5 + s, for s = ÷ C. 5x 2 + 3x, for x = 2 5(2) 2 + 3(2) 5(4) + 3(2) Substitute 15 for s. Divide. Add. Substitute 2 for x. Evaluate the power. Multiply. Add.

1-6 Variables and Algebraic Expressions Check It Out: Example 2A Evaluate the expression for the given value of the variable. A. 3x – 2 for x = 3 3(3) – 2 9 – 2 7 Substitute 3 for x. Multiply. Subtract.

1-6 Variables and Algebraic Expressions Check It Out: Example 2 B. r ÷ 3 + r, for r = ÷ C. 4y 2 + 2y, for y = 3 4(3) 2 + 2(3) 4(9) + 2(3) Substitute 12 for r. Divide. Add. Substitute 3 for y. Evaluate the power. Multiply. Add.

1-6 Variables and Algebraic Expressions Evaluate Additional Example 3: Evaluating Algebraic Expressions with Two Variables 6a6a + 4b, for a = 3 and b = 2. 6a6a + 4b (2) Substitute 3 for a and 2 for b. Divide and multiply from left to right. Add.

1-6 Variables and Algebraic Expressions Check It Out: Example 3 Evaluate 8w8w + 2x, for w = 4 and x = 2. 8w8w + 2x (2) Substitute 4 for w and 2 for x. Divide and multiply from left to right. Add.

1-6 Variables and Algebraic Expressions 1. Evaluate m + 4 for m = 19. A. 21 B. 27 C. 23 D. 28 Lesson Quiz—Have you mastered the target? Put your name on a half sheet of paper. Work the problem and write the letter choice that matches your answer.

1-6 Variables and Algebraic Expressions 2. Evaluate 7x – 8 for x = 5. A. 20 B. 27 C. 22 D. 32 Lesson Quiz for Student Response Systems

1-6 Variables and Algebraic Expressions 3. Evaluate 6x 2 + 5x for x = 5. A. 185 B. 85 C. 175 D. 50 Lesson Quiz for Student Response Systems

1-6 Variables and Algebraic Expressions 4. Evaluate + 5y for x = 3 and y = 5. A. 38 B. 44 C. 54 D. 64 Lesson Quiz for Student Response Systems 39 y

1-6 Variables and Algebraic Expressions 5. The expression 12n gives the number of months in n years. Evaluate 12n for n = 3. How many months are in 3 years? A. 12 months B. 24 months C. 36 months D. 48 months Lesson Quiz for Student Response Systems

1-6 Variables and Algebraic Expressions Homework Do the circled problems on the back of your notes page. Show your substitutions!!! Show the order of operations when necessary.