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.
Equation. in mathematics, the analytical form of the problem of finding those inputs for which two given functions have equal outputs. The functional inputs are usually called unknowns, and the unknowns for which the functional outputs are equal are called solutions or roots.