Solving Addition and 1 3 Subtraction Equations Warm
Solving Addition and 1 -3 Subtraction Equations Warm Up Write an algebraic expression for each word phrase. 1. 2. 3. 4. a number x decreased by 9 5 times the sum of p and 6 2 plus the product of 8 and n the quotient of 4 and a number c Pre-Algebra
Solving Addition and 1 -3 Subtraction Equations Learn to solve equations using addition and subtraction. Pre-Algebra
Solving Addition and 1 -3 Subtraction Equations An equation uses an equal sign to show that two expressions are equal. All of these are equations. 3 + 8 = 11 r + 6 = 14 24 = x – 7 100 = 50 2 To solve an equation, find the value of the variable that makes the equation true. This value of the variable is called the solution of the equation. Pre-Algebra
Solving Addition and 1 -3 Subtraction Equations Additional Example 1: Determining Whether a Number is a Solution of an Equation Determine which value of x is a solution of the equation. x + 8 = 15; x = 5, 7, or 23 Pre-Algebra
Solving Addition and 1 -3 Subtraction Equations Try This: Example 1 Determine which value of x is a solution of the equation. x – 4 = 13; x = 9, 17, or 27 Pre-Algebra
Solving Addition and 1 -3 Subtraction Equations Addition and subtraction are inverse operations, which means they “undo” each other. To solve an equation isolate the variable. This means getting the variable alone on one side of the equal sign. Pre-Algebra
Solving Addition and 1 -3 Subtraction Equations To solve a subtraction equation, like y 15 = 7, you would use the Addition Property of Equality. ADDITION PROPERTY OF EQUALITY Words You can add the same number to both sides of an equation, and the statement will still be true. Pre-Algebra Numbers Algebra 2+3=5 +4 +4 2+7=9 x=y x+ z = y + z
Solving Addition and 1 -3 Subtraction Equations Subtracting a smaller number from a larger number is the same as finding how far apart the two numbers are on a number line. Subtracting an integer is the same as adding its opposite. SUBTRACTING INTEGERS Words Change the subtraction sign to an addition sign and change the sign of the second number. Pre-Algebra Numbers Algebra 2 – 3 = 2 + (– 3) 4 – (– 5) = 4 + 5 a – b = a + (–b) a – (–b) = a + b
Solving Addition and 1 -3 Subtraction Equations Additional Example 2 A: Solving Equations Using Addition and Subtraction Properties Solve. A. 10 + n = 18 Pre-Algebra
Solving Addition and 1 -3 Subtraction Equations Additional Example 2 B: Solving Equations Using Addition and Subtraction Properties Solve. B. p – 8 = 9 Pre-Algebra
Solving Addition and 1 -3 Subtraction Equations Additional Example 2 C: Solving Equations Using Addition and Subtraction Properties Solve. C. 22 = y – 11 Pre-Algebra
Solving Addition and 1 -3 Subtraction Equations Try This: Example 2 A Solve. A. 15 + n = 29 Pre-Algebra
Solving Addition and 1 -3 Subtraction Equations Try This: Example 2 B Solve. B. p – 6 = 7 Pre-Algebra
Solving Addition and 1 -3 Subtraction Equations Try This: Example 2 C Solve. C. 44 = y – 23 Pre-Algebra
Solving Addition and 1 -3 Subtraction Equations Additional Example 3 A A. Jan took a 34 -mile trip in her car, and the odometer showed 16, 550 miles at the end of the trip. What was the original odometer reading? Pre-Algebra
Solving Addition and 1 -3 Subtraction Equations Additional Example 3 B B. From 1980 to 2000, the population of a town increased from 895 residents to 1125 residents. What was the increase in population during that 20 -year period? Pre-Algebra
Solving Addition and 1 -3 Subtraction Equations Try This: Example 3 A A. Isabelle earned $27 interest and now has a balance of $535 in the bank. What was her balance before interest was added? Pre-Algebra
Solving Addition and 1 -3 Subtraction Equations Try This: Example 3 B B. From June to July, the water level in a lake has increased from 472 feet to 502 feet. What was the increase in water level during that 1 -month period? Pre-Algebra
Solving Addition and 1 -3 Subtraction Equations Assignment Write the following assignment in your agenda and on the top of your paper: Lesson 1 -3: #1 -12 If you did not clean out your binder on Friday please do so today. File all notes and quizzes, and recycle everything else. Pre-Algebra
Solving Addition and 1 -3 Subtraction Equations Warm-up Determine which value of x is a solution of the equation. 1. x + 9 = 17; x = 6, 8, or 26 2. x – 3 = 18; x = 15, 18, or 21 Solve. 3. a + 4 = 22 4. n – 6 = 39 5. The price of your favorite cereal is now $4. 25. In prior weeks the price was $3. 69. Write and solve an equation to find n, the increase in the price of the cereal. Pre-Algebra
Solving Addition and 1 -3 Subtraction Equations Assignment Pre-Algebra
Solving Addition and 1 -3 Subtraction Equations Assignment Write the following assignment in your agenda and on the top of your paper: Lesson 1 -3: #14 -38 even Remember to bring me your agenda with this assignment written in it if I need to sign your agenda book. Pre-Algebra
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