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.
Both use numbers and variables; however it is all based on the arrangement. So let's take look at both to determine their use and relationship. An expression is a combination of numbers, variables, and symbols to be calculated. An equation contains expressions that are separated by an equals sign. A further look at the mathematical expression can be explained with numbers and variables such as: 7x + y - 4.