The rule
The rule is the part that still works when you try new examples. Graphs puts it in context with practice.
Why it works
Example: multiplying both sides of a true equation by the same nonzero number gives another true equation, because every term was scaled by the same factor.
Small numbers
Try 2 + 3 = 5. Multiply both sides by 4: 8 + 12 = 20. Still true. That is the same idea as “do the same thing to both sides” when you solve.
Test it
The rule A quick test
Try values
Core lesson
Go deeper: Graphs. Use the calculators below with your own loan or bill numbers, not only the examples on this page.
Use the calculator
FAQ
- Where is the main lesson?
Graphs has the full topic, examples, and practice links.
- Which calculator first?
After your setup is on paper, open Graphing calculator for a quick numeric pass.