Then you can figure out which is the independent variable and which is the dependent variable: (Independent variable) causes a change in (Dependent Variable) and it isn't possible that (Dependent Variable) could cause a change in (Independent Variable). For example: (Time Spent Studying) causes a change in (Test Score) and it isn't possible that (Test Score) could cause a change in (Time Spent Studying).
Domain and Range. When we look at a function like f(x) = x + 2, we can easily say where the function f(x), in this case, the value along the y-axis, is at any point we choose along the x-axis. We know that at x = 3.4, f(x) = 5.4. The values of x that the function will output a value for is called the domain of f. In the case of f(x) = x + 2, the domain is the entire x-axis, or, formally speaking, all real numbers. The values which f(x) takes on is called the range of f.
1 For x in the domain (- â , - 1] , the range of x - 1 is given by [0,+â), which gives a range of f(x) = - â(x -1) in the interval (- â , 0]. 2  Write f as an equation, square both sides and solve for x, and find the inverse.