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. Which x is NOT allowed for f(x) = 1/(x - 6)?
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   6
2. True or false: x = 5 is in the domain of f(x) = 1/(x - 5)
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   False
3. Domain of f(x) = 1/(x - 1)
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   x ≠ 1
4. f(x) = x + 4, g(x) = 2x. Find g(f(2))
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   12