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.
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.