Solving Addition and Subtraction Equations

Inverse operation is an operation that “undoes” another operation.Addition and subtraction are inverse operation.

Equivalent equations are two equations that have the same solution(s)

Subtraction Property of Equality

Subtracting the same number from each side of an equation produces an equivalent equation.

Algebra: x + a = b x + a – a = b - a

Addition Property of Equality

Adding the same number to each side of an equation produces an equivalent equation.

Algebra: x - a = b x – a + a = b + a

Modeling

Solve x − 5 = −1.

Practice

1. p − 5 = −2 2. w + 13.2 = 10.4

Practice

2 = 1.3 + a + 4

Real-life Application

A company has a profit of $120.50 today. This profit is $145.25 less than the profit P yesterday. Write an equation that can be used to find P. Then, solve for P.

HW: 1,2, 3, 7, 11, 15, 18 – 20, 21, 25, 29-33 odds