In Math 10 this week we stated a new unit called Relation and Functions. Relations are when the the independent variable, x, has multiple connections to dependent variables, y. Functions are when each independent variable has a special connection to one dependent variable.

Often written as f(x), if f(x) = 3x + 5

f(9) = 3(9) + 5

f(9) = 32, where the x variable, 9, has the pair of 32 as the y variable                                      on a graph. This would be a point of the graph. Another way of putting                                      this in words is that 9 is the domain and 32 is the range.

Domain is the set of all the numbers for the independent variable in the relation or function.    Range is the set of all numbers for the dependent variable in the relation or function.            So if we were given the domain { -2, -1, 0, 1, 2 } and the function f(x) = 3x^2 -4 then we can find the range { 8, -4, -1} because all we have to do is replace x in the expression with each number of the domain individually and solve.

These have a connection to the last unit we learned with expressions because often there are inputs that are integers and the output are expressions we were introduced to before.