8th Grade · Expressions & Equations
Identity
8.EE.C.7a
Definition
An equation that holds true for all values of the variable because both sides are equivalent expressions. It has infinitely many solutions.
Teach it
Where it is taught, with guided notes, practice, homework, an exit ticket and an interactive Teacher Deck.
Examples
- 3(x+2) = 3x+6 simplifies to 3x+6 = 3x+6 — true for every x.
- Try x = 0: 6 = 6. Try x = 5: 21 = 21. Always true.
Key rule
An identity simplifies to the same expression on both sides.
Memory hook
True no matter what x is.