Chapter 3-3 Solve Equations by Adding/Subtracting Unit 1 Chapter 3-3 Solve Equations by Adding/Subtracting

Solve equations by subtracting You can used inverse operations to solve equations. Inverse Operations “undo” each other. You can use the Subtraction Property of Equality to solve equations involving addition Example 1: X + 3 = 7 (Move the 3 because it is on the same side of the equal sign as the variable) - 3 -3 X = 4 Example 2: 16 + X = 12 -16 -16 (move the 16 because it is on the same side of the equal sign as the variable) X = - 4

Solve equations by adding You can solve some equations by adding the same number to each side. This property is called the Addition Property of Equality. Ex 1) Y – 7 = 21 (move the 7 since it’s on the same side of the equal sign as the variable) + 7 + 7 Y = 28 Ex 2) X – 10 = -10 + 10 +10 X = 0

Let’s try some examples Ex 1) X + 7 = - 8 Ex 2) X – 8 = 15 Ex 3) X + 2 =10 Ex 4) A – 3 = 13 Ex 5) 23 + Y =14 Ex 6)* C – (-3) = 9

Let’s check our answers Ex 1) X + 7 = - 8 X = -15 Ex 2) X – 8 = 15 X = 23 Ex 3) X + 2 = 10 X =8 Ex 4) A – 3 = 13 A = 16 Ex 5) 23 + Y =14 Y = - 9 Ex 6)* C – (-3) = 9 C = 6