Definition of dray. : a vehicle used to haul goods; especially : a strong cart or wagon without sides.
The main difference between an equation and a function is the fact that an equation usually deals with a single input, whereas, a function can have numerous inputs. In mathematics, an equation is used to denote the equality between two expressions.
Equations and Expressions are closely related. The primary difference between the two is an equals sign. An equation has a left side, a right side and an equals sign separating the sides. An expression, by contrast, doesn't have any sides and is simply what the name suggests: An algebraic expression..