7th Grade · Expressions & Equations

Solution

7.EE.B.4a

Definition

The value of the variable that makes an equation true. Check by substituting the value back into the original equation — if both sides are equal, it is the solution.

Examples

  • For 3x - 1 = 8: x = 3 gives 3(3) - 1 = 8, true — x = 3 is the solution.
  • x = 2 gives 3(2) - 1 = 5, not 8 — x = 2 is NOT a solution.

Key rule

A linear equation in one variable has exactly one solution (unless it has no solution or infinitely many).

Memory hook

Substitute back in — does it balance?