Warm – Up! Evaluate if a=3, x=2, y=5, and z=4 4(yz +2) – a Simplify each expression: 9 + 5 x 2 40 x 10 + 18 x 2 Insert grouping symbols in the following expression so that its value is 16.

1.1 Variables 1.2 Grouping Symbols 1.3 Equations Algebra I – Chapter 1 1.1 Variables 1.2 Grouping Symbols 1.3 Equations

Variables: A Variable is a symbol used to represent one or more numbers. The numbers are called the values of the variables. A variable expression is an expression that contains a variable such as 8n

Simplifying Expressions: When you simplify an expression you are replacing a numerical expression by the simplest name for its value. Ex: 4 + 2 Ex: 2y + 4y

Substitution Principal: An expression may be replaced by another expression that has the same value Ex: Evaluate each expression if a=5 (3a) + 2

You Try: Evaluate each expression if x=2, y=3 and z=4 5yz –x 8 + (9xy)

Grouping Symbols: Remember Order of Operations? PE MD AS Grouping symbols are very important within the order of operations. { = brace [ = bracket ( = parenthesis

You Try: If t=6, x=3, y=4, and z=5 Evaluate: 2[x + 4(y + z)]

Equations: An equation is formed by placing an equal sign between two numerical or variable expressions, called sides of the equation. Sentences containing variables are called open sentences. The given set of numbers that a variable may represent is called the domain.

Solutions Sets: Any value of a variable that turns an open sentence into a true statement is a solution, or root, of the sentence and is said to satisfy the sentence. The set of all solutions of an open sentence is called the solution set of the sentence. Finding the solution set is called solving the sentence.

Domains: The set of given numbers for any variable can also be shown: This is read as “x belongs to the set whose members are 1,2, and 3.” Solve 5x – 1 = 9 for the given domain.

Reflection: What is/ give example of: a variable expression: a grouping symbol: open sentence: solution/root:

Tonight’s Homework: Page 12 – Mixed Review 1-12 Page 13 – Self Test 1-6 Quiz (Sections 1.1-1.3 Weds)