Definition of dray. : a vehicle used to haul goods; especially : a strong cart or wagon without sides.
Expressions versus Equations. A difference between expressions and equations is what each represents. An expression shows a math relationship. One key to an expression is that there is no solution. An expression does not have an answer. An expression, however, can be evaluated. To evaluate an expression, substitute values for the variables.
An equation is simply a number sentence with a variable in the place of an unknown value. A variable is a letter that is substituted in place of the unknown value. It can be any letter you want, although x is most commonly used. To unlock this lesson you must be a Study.com Member.