Answer
$x-6=5$ does not belong with the other three because it can only be solved using either the Addition Property or Subtraction Property of Equality.
The three other equations can be solved by either the Multiplication Property of the Division Property of Equality.
Work Step by Step
The equations $8=\frac{x}{2}$, $3=x\div 4$, and $\frac{x}{3}=9$ can all be solved using either the Multiplication Property of Equality of Division Property of Equality.
The equation $x-6=5$ can only be solved using either Addition Property of Equality or Subtraction Property of Equality. Hence, it is the equation that does not belong with the other three.
