Factor Theorem Calculator

Test whether x-r is a factor of a polynomial by evaluating P(r).

PolynomialsAlgebraPrecalculus

Calculator

Polynomial coefficients
r in factor x - r
Please enter valid values.

What this calculator teaches

The Factor Theorem connects roots and factors. If r is a root, then x-r is a factor.

This calculator is a fast way to check factor candidates from the Rational Root Theorem.

Formula & Symbols

ConceptFormulaMeaning
Factor theoremP(r)=0 ⇔ (x-r) is a factorA zero value means the binomial divides the polynomial exactly.
Remainder theoremremainder=P(r)The value P(r) is the remainder after division by x-r.

Step-by-Step Examples

Example 1
Test x - 1 for x² - 3x + 2
  • Use r=1.
  • P(1)=1-3+2.
  • P(1)=0.
✓ x - 1 is a factor.

Where students use this

🎓
High school and college
Use the calculator to check homework and understand each step.
📊
Modeling and data
Connect formulas to tables, graphs, and real values.
🧪
Science and engineering
Use the result inside physics, chemistry, engineering, and lab problems.
💻
Computer science
Apply the same math to algorithms, simulations, and numerical work.

Common Mistakes to Avoid

⚠️
Mixing notation with calculator input

Mathematical notation is compact, but calculators need explicit numbers and operators.

⚠️
Skipping domain restrictions

Some formulas only work when denominators are nonzero, logs have positive inputs, and square roots are valid.

⚠️
Rounding too early

Keep extra decimals while solving and round only the final answer.

Frequently Asked Questions

Is this calculator for learning or only answers? ▾
It is designed for both. The result panel gives the answer, while the examples and explanation show why the method works.
Can I use decimals and negatives? ▾
Yes, unless the specific topic has a restriction such as a positive base, positive radicand, or nonzero denominator.
Why might my answer differ from a textbook? ▾
Different rounding, equivalent algebraic forms, or a different interpretation of the input can produce a different-looking but equivalent result.
Does this replace solving by hand? ▾
No. It helps verify work and understand the steps, but students should still practice the method manually.

Related Math Calculators

Formula Explorer connections

Interpretation: This formula describes an algebraic relationship among variables, functions, equations, roots or sequences. Assumption: Respect the expression’s domain and excluded values. Check roots in the original equation because transformations can introduce extraneous solutions.

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