Domain
See It in Action
Two examples of the idea done right—and one common look-alike that is not right.
EXAMPLE
EXAMPLE
NON-EXAMPLE
Definition
In Algebra 1, the domain of a function refers to the set of all possible input values (usually represented by x) for which the function is defined.
In other words, the domain of a function is just the set of all the numbers you can use as inputs for that function. It tells you which numbers you can safely put into the function without causing any problems.
Think of it this way:
If you have a function like f(x) = 1/(x-4), you can use almost any number for x. But if you try to use x = 4, you get a problem because you can't divide by zero. So, the domain is all numbers except x = 4.
So, the domain is all the possible values you can plug into your function without running into issues.