What You Will Learn To Do Today
By the end of this lesson, you should be able to:
- Solve equations with fraction coefficients, including by clearing fractions
- Solve equations with decimal coefficients by clearing decimals
- Distribute and collect like terms to solve an equation
- Solve multi-step equations combining all of these skills
- Verify a solution by substituting it back in
Two Ways to Solve It
- Direct: subtract
, then multiply by → - Clear fractions: multiply every term by
→ →
Multiplying both sides by 3 is the multiplication property of equality.
Clearing Fractions With the Common Denominator
To clear fractions, multiply every term by the LCD.
- The fractions all turn into whole numbers
- You're left with an equation you already know how to solve
- "Multiply both sides" means multiply every term
When Clearing Fractions Really Shines
The LCD of
Check Every Term Got Multiplied
In
| Term | |
|---|---|
The middle term is the one people forget.
Decimals Are the Same Idea
- Direct: subtract
, divide by → - Clear decimals: multiply every term by
→
Since
Watch the Direction of the Division
Solving
"Zero-point-three of
Your Turn: Pick a Strategy
- Notice
- Clear by multiplying by
, or by - Either works — which is cleaner here?
New Tools for Messy Structure
Clearing fractions handled ugly numbers. Now: ugly structure.
- Distribute to remove parentheses
- Collect like terms to simplify each side
- Then solve the equation you already know
Distribute to Every Term Inside Parentheses
- Distribute:
- Note
, not - Collect left:
Your Turn: Finish Solving This One
From
- Subtract
from both sides - Add
to both sides - Then divide — what is
?
Work each step, then advance to check.
Say "Subtract," Not "Move It"
Say it as an operation on both sides:
The sign change is a result of subtracting — not a separate rule.
Collect With Variables on Both Sides
- Combine left:
- Subtract
, add : - Divide by
:
Combine Every Skill in One Equation
The Same Equation, Distributing First
- Distribute:
- Still solvable — but every step carries fractions
Both paths give
Find the Error in This Expansion
A student expands
What did they forget? Write the correct expansion.
Quick Check: Solve This Solo
- Solve it on your own
- Then substitute your answer back in
Commit to an answer before you advance.
Multi-Step, From Start to Finish
Solve completely, then check:
No scaffolding. Clear fractions, distribute, collect, solve, verify.
When the Answer Is "No Solution"
- Clear and simplify carefully
- The variable cancels and leaves a false statement
- No solution — exactly the case from 8.EE.C.7.a
Four Common Traps to Avoid Here
Distribute to every term —
When clearing, multiply every term, even whole numbers
"Move it" really means subtract from both sides — keep the sign right
To undo
What You Now Understand About Solving
✓ Clearing fractions or decimals turns hard equations into familiar ones
✓ Distribute and collect to tame any structure
✓ A messy equation is a clean one in a costume
Coming Up Next: Solving Systems
You can now solve any single linear equation.
Next you'll solve systems — two equations at once (8.EE.C.8). The clearing, distributing, and collecting you mastered today are the engine inside substitution and elimination.