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.
Tweet. Key difference: In mathematics, an equation is used to denote the equality between two expressions. A function, on the other hand, is in much more complex than an equation. A function is used to denote a relation between a set of inputs and a set of corresponding outputs. Essentially, an input should give a single output. A function is a relationship between two variables.