solving two-step equations

SolvingSolving Two-Step Two-Step EquationsEquations

Teacher: Jimmy Frost

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/4 + 3 = 12

c) 5n + 4 = 6

d) n/2 – 6 = 4

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.

Ex. 1: Solve 4x – 5 = 11

4x – 5 = 15 +5 +5 (Add 5 to both sides)4x = 20 (Simplify) 4 4 (Divide both sides

by 4)x = 5 (Simplify)

Try These Examples1. 2x – 5 = 17

2. 3y + 7 = 25

3. 5n – 2 = 38

4. 12b + 4 = 28

Check your answers!!!1. x = 11

2. y = 6

3. n = 8

4. b = 2

Ready to Move on?

Ex. 2: Solve x/3 + 4 = 9

x/3 + 4 = 9 - 4 - 4 (Subt. 4 from both sides)x/3 = 5 (Simplify)

(x/3) 3 = 5 3 (Mult. by 3 on both sides)

x = 15 (Simplify)

Try these examples!

1. x/5 – 3 = 8

2. c/7 + 4 = 9

3. r/3 – 6 = 2

4. d/9 + 4 = 5

Check your answers!!!

1. x = 55

2. c = 35

3. r = 24

4. 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 Subtaction2. Undo Multiplication or Division

That’s All!