Domain of a rational function

What this lesson shows

f(x) = 1 / (x − 2). A fraction machine: 1 divided by, x minus 2. Most inputs are fine… but one of them breaks this machine. Can you spot it before it happens?

Try it yourself

Real questions from this lesson's worksheets — answers below each one.

1. Domain of f(x) = 1/(x - 1)
   Show answer

   x ≠ 1
2. True or false: x = 5 is in the domain of f(x) = 1/(x - 5)
   Show answer

   False
3. Which x is NOT allowed for f(x) = 1/(x - 16)?
   Show answer

   16
4. Domain of f(x) = 1/(x - 2)
   Show answer

   x ≠ 2