Domain of a function worksheet for Algebra 2
A square root cannot take a negative, so the domain is whatever keeps the inside at zero or above. That turns every question into an inequality you already know how to solve. A fraction cannot have zero on the bottom, so a rational function loses the x values that make its denominator zero.
Also taught in Algebra 1 and Precalculus, each at its own level and with its own examples.
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Sigma Prep · sigmaprep.io/worksheets Name Domain of a Function Date Period State the domain in interval notation.
Free math worksheets at sigmaprep.io/worksheets© 2026 Sigma Prep |
Sigma Prep · sigmaprep.io/worksheets Name Domain of a FunctionAnswer keyVersion 1 Date Period State the domain in interval notation.
Free math worksheets at sigmaprep.io/worksheets© 2026 Sigma Prep |
How to do these
State the domain of
- The inside cannot be negative: 3x - 12 is at least 0.
- Add 12, then divide by 3.
The answer is .
Where students go wrong
Forgetting to flip the sign when the coefficient is negative. The domain of the square root of 12 - 3x is x at most 4, not x at least 4, because dividing by the negative turns the inequality round.
Also called finding the domain, domain of a radical function or allowed input values.
What you can put on this worksheet
- The domain of a square root
- State the domain of →
- Rational, root-in-denominator and log
- State the domain of →