Article Contents
- What are Equivalent Equations?
- Rules for Creating Equivalent Equations
- Visual Examples
- Practice Problems
- Interactive Exercises
1. What are Equivalent Equations? {#what-are-equivalent-equations}
Equivalent equations are equations that have the same solution(s).
If x=3 makes equation A true, and x=3 also makes equation B true, then A and B are equivalent.
Example
These three equations are all equivalent (they all have x=5 as their solution):
| Equation | Verification |
| x+2=7 | 5+2=7✓ |
| x=7−2 | x=5✓ |
| 2x=10 | 2(5)=10✓ |
2. Rules for Creating Equivalent Equations {#rules-for-creating-equivalent-equations}
The balance principle gives us these rules:
Rule 1: Add the Same Number to Both Sides
x−3=7⇔x−3+3=7+3⇔x=10
Rule 2: Subtract the Same Number from Both Sides
x+5=12⇔x+5−5=12−5⇔x=7
Rule 3: Multiply Both Sides by the Same Number
x/2=6⇔x/2×2=6×2⇔x=12
Rule 4: Divide Both Sides by the Same Number (non-zero)
3x=15⇔3x/3=15/3⇔x=5
Rule 5: Swap Sides (Reflexive Property)
x+2=7⇔7=x+2
3. Visual Examples {#visual-examples}
Starting with: x+4=12
Step 1: x + 4 = 12
Step 2: x = 12 - 4 (subtract 4 from both sides)
Step 3: x = 8 (calculate)
Each step produces an equivalent equation.
Starting with: 2x+3=11
Step 1: 2x + 3 = 11
Step 2: 2x = 11 - 3 (subtract 3 from both sides)
Step 3: 2x = 8 (calculate)
Step 4: x = 8/2 (divide both sides by 2)
Step 5: x = 4 (calculate)
All equations in this chain are equivalent!
4. Practice Problems {#practice-problems}
Problem 1
Which equation is equivalent to x+6=14?
- A) x=14+6
- B) x=14−6
- C) x=14×6
- D) x=14÷6
Answer: B (
x=14−6=8)
Problem 2
Which transformation of 3x=21 gives an equivalent equation?
- A) Add 3 to both sides
- B) Subtract 3 from both sides
- C) Divide both sides by 3
- D) Multiply both sides by 3
Answer: C (
x=7)
5. Interactive Exercises {#interactive-exercises}
Test your understanding of equivalent equations:
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