Pre Test Translate each word into a mathematical

Pre Test Translate each word into a mathematical operation. 1) increase + 6) plus 2) 3) 4) 5) − + − • 7) 8) 9) 10) decrease more than less than product difference quotient sum times + − ÷ + • Write and answer the following problems. 11) Simplify. − 42 12) Write 2 y • 2 y in exponential form.

1 -1 Variables and Expressions You would be wise to listen carefully and take notes! Algebra 1 Be smart correct your odd homework problems after you complete them! Glencoe Mc. Graw-Hill Linda Stamper

In algebra, variables are symbols used to represent unspecified numbers or values. Any letter may be used as a variable. An expression that represents a particular number is called a numerical expression. Example: 3 + 2 An algebraic expression consists of one or more constants and variables along with one or more arithmetic operations. constants - numbers variables - letters operations - addition, subtraction, multiplication and division Example of an algebraic expression: 3 x + 2

In algebraic expressions, a raised dot or parentheses are often used to indicate multiplication as the symbol x can be easily mistaken for the variable x. Here are some ways to represent the product of x and y. Use good form in an answer! In each expression, the quantities being multiplied are called factors, and the result is called the product.

An expression like 43 is called a power. base 43 exponent or power word form: four to the third power four cubed factor form: 4 • 4 evaluated form: 64 To evaluate an expression means to find its value. The word power can also refer to the exponent.

Writing Algebraic Expressions In English there is a difference between a phrase and a sentence. Phrases are translated into mathematical expressions. Sentences are translated into equations or inequalities. The sum of 6 and a number Phrase 6 + n Sentence The difference of a number and three is five. n – 3 = 5 Sentence Seven times a number is less than 50. 7 n < 50 When choosing a variable for an unknown, it may be helpful to select a Sentences letter that must relates to the unknown value (for example: let have a represent a verb! age). If a variable is given use it!

The product of five and a number 5 n The product of a number and five Would you say 5 notebooks or notebooks 5? 5 n Write your answer in good form - the number comes before a variable in a term involving multiplication.

Write an algebraic expression for each word phrase. a. The difference of a number and 7 n– 7 b. 32 increased by a number 32 + n c. 25 less than a nnumber – d. 10 less the product of 5 and a number cubed 10 – 5 n 3 e. The quotient of a number and six. n Use a fraction 6 bar to designate division!

Example 1 Write the phrase as an algebraic expression. a. 11 greater than a number n + 11 b. a number subtracted from 15 Did you use a fraction bar to designate division? 15 – n c. The sum of a number and 30 n + 30 d. Maria’s age minus 27 a – 27 18 e. The quotient of 18 and a number n f. The sum of a number and ten, divided by two.

Example 2 Write the phrase as an algebraic expression. a. eight more than a number n+8 b. seven less the product of 4 and a number x 7 – 4 x c. n cubed divided by 2 d. 9 more than the quotient of b and 5 e. one third the original area of a f. thirteen less than a number n - 13

Write in exponential form (as a power). Example 3 Example 4 Example 5 y • y • y 3 x • 3 x 5 • 5 (3 x)4 53 y 4 Evaluate. Example 6 2 • 2 • 2 16 Example 7 5 • 5 125 Must have parentheses! Example 8 (-3)2 -32 -9 9 A power applies only to what is directly in front of it.

Pre Test Write and answer the following problems in your spiral notebook. 1) Simplify. − 42 − 16 3 2) Write 2 y • 2 y in exponential form. (2 y) − 4 • 4 A power applies only to what is directly in front of it. The 2 y must be in parentheses!

1 -A 2 Pages 8– 9, #13– 29, 46– 54.