Solving Multi-Step Equations - Complete Interactive Lesson
Part 1: Leveling Up Your Equation Skills ๐
Leveling Up Your Equation Skills ๐
In Grade 6 you solved one-step equations like or . Those took a single move to crack.
A multi-step equation needs two or more steps to get the variable alone. They combine the operations you already know, so you'll have to undo them one at a time โ in the right order.
Examples of multi-step equations:
- โ two steps (subtract, then divide)
- โ three steps (distribute, add, divide)
- โ variables on sides!
Your goal never changes: get the variable alone on one side of the equal sign.
The Strategy: Unwrap the Present ๐
Think of an equation like a wrapped gift. The variable is hidden inside, with layers of operations wrapped around it. To reach it, you unwrap in reverse order.
You already know PEMDAS โ the order you build an expression:
Parentheses โ Exponents โ Multiply/Divide โ Add/Subtract
To solve, you run that order backwards (reverse PEMDAS):
- Simplify first โ combine like terms and distribute parentheses.
- Undo addition / subtraction โ do the opposite to both sides.
- Undo multiplication / division โ do the opposite to both sides.
The Golden Rule: Whatever you do to one side, you must do to the other side. That keeps the equation balanced, like a scale. โ๏ธ
A First Worked Example
Solve:
Step 1 โ Undo the addition. Subtract from both sides:
Quick Concept Check โ
Let's make sure the big idea stuck.
Part 2: Worked Examples: Two-Step Equations โ๏ธ
Worked Examples: Two-Step Equations โ๏ธ
Example A โ Subtraction then division: Solve
Step 1 โ Add to both sides (undo the subtraction):
Part 3: Guided Practice: Choose the Answer
Guided Practice: Choose the Answer ๐ฏ
Work each one carefully on scratch paper, then pick the matching answer.
Fill in the Solving Steps ๐งฉ
Below is the work for solving . Choose the option that correctly fills each blank.
Part 4: Equations in the Real World ๐
Equations in the Real World ๐
Multi-step equations are perfect for real situations that have a starting fee plus a per-item cost.
Example โ Bowling night: A bowling alley charges $3 to rent shoes plus $5 per game. You spent $23 total. How many games did you play?
Set up the equation. Let = number of games:
The is the cost of the games, and the is the one-time shoe fee.
Part 5: Putting It All Together
๐ Putting It All Together
You can now solve equations that take several steps. Here's the game plan to lock it in:
| Step | What To Do | Why |
|---|---|---|
| 1. Simplify | Distribute parentheses, combine like terms | Clears clutter so you can see the equation |
| 2. Undo / | Add or subtract on both sides | Reverse PEMDAS: addition comes last to build, so undo it first |
| 3. Undo / |