Bell Ringer
• X-7=18
-4x=18
• x/9=-12
-4=5+x
How do we solve an equation???
• Do inverse operations
• ie. If something is added, you subtract
(vice-versa); if something is multiplied, you
divide (vice-versa)
Solve the following equations
• 5/6 x = -15
-¾ x=-2
• x/-4 = 3
2/5 x = 1
Solving Two-Step Equations
Teacher: Mrs. Piotrowsky
What is a Two-Step Equation?
An equation written in the form
Ax + B = C
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 =
+5
4x
=
4
x=5
15
+5 (Add 5 to both sides)
20 (Simplify)
4 (Divide both sides by 4)
(Simplify)
Try These Examples
1. 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
How did you do? Are you
ready for more???
Ex. 2: Solve x/3 + 4 = 9
x/3 + 4 = 9
-4 -4
x/3 = 5
(Subt. 4 from both sides)
(Simplify)
(x/3)  3 = 5  3 (Mult. by 3 on both sides)
x = 15
(Simplify)
What happens when I have a
problem like this???
• -5 + 1/3 x = -12
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 Subtaction
2. Undo Multiplication or Division
Quiz Friday: Solving 1 and 2 step equations
•
Let’s Practice!!!