3.2 Solving Equations by Using Addition and Subtraction Addition Property of Equality –If the same number is added to each side of an equation, the resulting equation is true. –For any numbers a, b, and c, if a = b, then a + c = b + c. If the same number is added to each side of an equation, then the result is an equivalent equation. Equivalent equations have the same solution.

Solve by Adding a Positive Number Solve m – 48 = 29. Then check your solution. m – 48 = 29 m – = m = 77 Check: m – 48 = – 48 = = 29 The solution is 77.

Solve by Adding a Negative Number Solve 21 + q = -18. Then check your solution q = q + (-21) = (-21) q = -39 Check: 21 + q = (-39) = = -18 The solution is -39.

Subtraction Property of Equality If the same number is subtracted from each side of an equation, the resulting equation is true. For any numbers a, b, and c, if a = b, then a – c = b – c.

Solve by Subtracting Solve d = 97. Then check your solution d = d – 142 = 97 – 142 d = - 45 Check: d = (-45) = = 97 The solution is -45.

Solve an Equation Solve

Write and Solve an Equation Write an equation for the problem. Then solve the equation and check your solution. A number increased by 5 is equal to 42. Find the number. n + 5 = 42 n + 5 – 5 = 42 – 5 n = 37 Check: n + 5 = = = 42 The solution is 37.

More Practice!!!!! Homework – Worksheet 3.2.