Equation:  An equation is two expressions, numeric or algebraic, are set equal to each other. 

Examples:  2 + 3 = 5                x + 2 = 5          2x – 1 = -10

Linear Equation:  y = x + 4  x is the independent variable and  is the dependent variable

                                    When graphed on a coordinate system, the solutions will be a

                                    straight line.

Function:  A function is a rule that for every input ( domain, independent variable) there is one and only one output (range, dependent variable)

This is very similar to an equation, which can be a function.  However, some equations can have more than one output for one input.  Example:  y =  is an equation, but not a function because for x = 4, y = 2, and -2. 

Examples of functions in equation form and table form.

F(x) = x + 4    

 To determine if a graph is a function, you can use the vertical line test. 

  If a vertical line can pass through a graph and it intersects the graph

  only once, then it is a function.