Rational root theorem worksheet for Precalculus
Precalculus pushes the rational root theorem to cubics with a leading coefficient other than 1, where not every zero is rational. List the candidates, test them with synthetic division, and once one works, solve the quadratic that is left, which may give irrational or complex zeros.
Also taught in Algebra 2, at its own level and with its own examples.
Select your difficulty
Pick more than one for a sheet that mixes them.
The preview can look cramped on a phone. The PDF and printed sheet come out normal.
Free math worksheets at sigmaprep.io/worksheets© 2026 Sigma Prep
Sigma Prep · sigmaprep.io/worksheets Name Rational Zeros Date Period Solve each equation, or answer as asked.
Free math worksheets at sigmaprep.io/worksheets© 2026 Sigma Prep |
Sigma Prep · sigmaprep.io/worksheets Name Rational ZerosAnswer keyVersion 2 Date Period Solve each equation, or answer as asked.
Free math worksheets at sigmaprep.io/worksheets© 2026 Sigma Prep |
How to do these
Find all zeros of
- The candidates are ±1, ±2 and ±1/2, and f(1/2) = 0.
- Synthetic division by 1/2 leaves 2x² - 4x - 4, which is 2(x² - 2x - 2).
- The quadratic formula on x² - 2x - 2 = 0 gives 1 ± √3.
The answer is .
Where students go wrong
Writing the fractions upside down. The top comes from the constant and the bottom from the leading coefficient, so for 4x³ + 2x² + 3x - 7 the candidate is 7/4, not 4/7.
Also called rational zero theorem, finding rational zeros or possible rational roots.
What you can put on this worksheet
- Zeros that are fractions
- →
- List the possible rational zeros
- List the possible rational zeros of →
- All zeros, some irrational or complex
- Find all real and complex zeros of →
- Higher degree lists, quartics, a repeated zero
- Find all rational zeros: →