Solving Two-Step Equations

What IS A TWO STEP EQUATIONS? What you do to one side of the equation must also be done to the other side to keep it balanced. An equation is like a balance scale because it shows that two quantities are equal.

What is a Two-Step Equation? An equation written in the form Ax + B = C

Examples of Two-Step Equations a)3x – 5 = 16 b)y + 3 = 12 4 a)5n + 4 = 6 b)n – 6 = 4 2

Steps for Solving Two-Step Equations 1.Solve for any Addition or Subtraction on the variable side of equation by “undoing” the operation from both sides of the equation. 2.Solve any Multiplication or Division from variable side of equation by “undoing” the operation from both sides of the equation.

Opposite Operations Addition  Subtraction Multiplication  Division

Helpful Hints? Identify what operations are on the variable side. (Add, Sub, Mult, Div) “Undo” the operation by using opposite operations. Whatever you do to one side, you must do to the other side to keep equation balanced.

Solving TWO STEP EQUATIONS What is the variable? To solve two step equations, you need to ask three questions about the equation: What operations are performed on the variable? What operations are performed on the variable? What is the inverse operation? What is the inverse operation? (The one that will undo what is being done to the variable)

Ex. 1: Solve 4x – 5 = 15 4x – 5 = (Add 5 to both sides) 4x = 20(Simplify) 4 4(Divide both sides by 4) x = 5(Simplify)

Try These Examples 1.2x – 5 = 17 A. x=6 B. x=11 2.3y + 7 = 25 A. y=6 B. y=7 3.5n – 2 = 38 A. n=10 B. n=8 4.12b + 4 = 28 A. b=2 B. b=3

Ready to Move on?

Ex. 2: Solve x + 4 = 9 3 x/3 + 4 = (Subt. 4 from both sides) x/3 = 5 (Simplify) x  3 = 5  3 (Mult. by 3 on both sides) 3 x = 15 (Simplify)

Try these examples! 1.x/5 – 3 = 8 A. x=1 B. x=11 2.c/7 + 4 = 9 A. c=5 B. c=35 3.r/3 – 6 = 2 A. r=24 B. r=8 4.d/9 + 4 = 5 A. d=1 B. d=9

Time to Review! Make sure your equation is in the form Ax + B = C Keep the equation balanced. Use opposite operations to “undo” Follow the rules: 1.Undo Addition or Subtaction 2.Undo Multiplication or Division