Solving Equations by 2-1 Adding or Subtracting Warm Up Holt Algebra 1 Warm Up Lesson Presentation Lesson Quiz

Objective Solve one-step equations in one variable by using addition, subtraction, multiplication or division.

Vocabulary Operation Inverse operation equation solution of an equation

Mathematical Operation: A process performed on two values Mathematical Operation: A process performed on two values. + - x / Inverse Operation: An operation that undoes another operation

Equations vs. expressions Expression: a grouping of numbers/variables and operations An equation is a mathematical statement that two expressions are equal.

A solution of an equation is a value of the variable that makes the equation true.

GOLDEN RULE OF EQUATIONS You can perform any operation on one side of an equation as long as you perform the exact same operation on the other side.

An equation is like a balanced scale An equation is like a balanced scale. To keep the balance, perform the same operation on both sides.

Some equations contain variables. Example: x + 2 = 5 SOLUTION: any value that makes an equation a true statement

To find solutions, isolate the variable. A variable is isolated when it appears by itself on one side of an equation, and not at all on the other side. x = 3

Isolate a variable by using inverse operations which "undo" operations on the variable. x + 2 = 5

3x = 18

x/2 = 10

REMEMBER! ½ x = 5 Dividing by a number is the same as multiplying by its reciprocal.