Drill Complete 2-1 Word Problem Practice #1 – 4 in your groups. 1 group will be chosen to present each problem.

2-2 Solving Equations Using Addition and Subtraction Objective: To solve equations by using addition and subtraction Open books to page 78.

(1.) Addition Property of Equality ** Definition: if a = b then a + c = b + c NOTE: You must add the same number to both sides of the equality. Example: if x = 5 then x + 2 = 7

(2.) Solve an Equation ** Definition: To solve an equation for a variable means to isolate the variable on one side of the equation with a coefficient of 1. Example: x = 4 Why is it important to solve equations? What does it mean for a variable to have a coefficient of 1?

Example 1* 1A: 32 = r – 8 1B: 7 = 42 + t

(3.) Equivalent Equations** Definition: Equations that have the same solution. Example: x = 10 x + 2 = 12 x + 4 = 14

(4.) Subtraction Property of Equality** Definition: For any numbers a, b, and c, if a = b then a - c = b - c NOTE: If you know that two numbers are equal then if you do the same thing to both of them (subtract a number) then the two sides will still be equal.

Solving Equations with Addition* 1.Isolate the variable. (Get the variable by itself by adding the additive inverse to both sides.) 2.Check the solution Example:x + 2 = x = = 4 (Check!)

Solving Equations with Subtraction* 1. Change all subtraction to addition by the additive inverse. 2.Isolate the variable. (Get the variable by itself by adding the additive inverse to both sides.) 3.Check the solution Example:x – 2 = 4 1. x + (-2) = x = – 2 = 4 (Check!)

Classwork 2-1 Study Guide (#2-18 EVEN) Homework 2-2 Practice (1 – 31 ODD)