परिमेय व्यंजक कैलकुलेटर
Simplify · Add · Subtract · Multiply · Divide · Evaluate · Domain Restrictions
Enter polynomial अंशs and हरs using standard notation (e.g. x^2-4, x+2). Get step-by-step factoring, cancellation, and the simplified result.
Simplify a Rational Expression
Factor & CancelQuick examples
Input notation guide
2x^2+3x-5 → 2x² + 3x − 5
x^2-9 → x² − 9 (difference of squares)
x^3-1 → x³ − 1 (difference of cubes)
4 → constant polynomial
x → linear monomial
-x+1 → −x + 1 (leading negative OK)
What Are Rational Expressions?
A rational expression is an algebraic fraction of the form P(x)/Q(x) where P and Q are polynomials and Q is not the zero polynomial. Rational expressions are the polynomial analog of ordinary numerical fractions — everything you can do with numeric fractions (add, subtract, multiply, divide, simplify) you can also do with rational expressions, following the exact same rules.
Everyday examples appear throughout algebra and precalculus: the slope formula, partial fraction decomposition in calculus, and asymptote analysis in graphing all involve rational expressions. Understanding how to simplify and operate on them is foundational for algebra, calculus, and engineering mathematics.
Because the हर Q(x) cannot equal zero, rational expressions always carry domain restrictions — values of x that must be excluded. For instance, (x+1)/(x-3) is undefined at x = 3, so the domain is all real numbers except 3. These restrictions are a core part of every answer involving rational expressions.
How to Simplify Rational Expressions
Simplification reduces a rational expression to its lowest terms by cancelling common factors from अंश and हर:
- Step 1 — Factor the अंश completely (GCF, difference of squares, quadratic formula, grouping, etc.).
- Step 2 — Factor the हर completely using the same set of techniques.
- Step 3 — Cancel common factors that appear in both अंश and हर.
- Step 4 — State domain restrictions from the original हर (including any factors that were cancelled).
Worked example — simplify (x²-9)/(x+3):
अंश: x²-9 = (x-3)(x+3). हर: (x+3). Cancel (x+3): result = (x-3), with restriction x ≠ -3.
Adding and Subtracting Rational Expressions
To add or subtract rational expressions you need a common हर, just like with ordinary fractions. The process is:
- Factor each हर to find the LCD (Least Common हर).
- Multiply each fraction top and bottom by the missing LCD factors.
- Combine the अंशs over the single LCD.
- Simplify the result if possible.
Worked example — add 2/x + 3/(x+1):
LCD = x(x+1). Rewrite: 2(x+1)/[x(x+1)] + 3x/[x(x+1)] = (2x+2+3x)/[x(x+1)] = (5x+2)/[x(x+1)], with restrictions x ≠ 0, x ≠ -1.
Multiplying and Dividing Rational Expressions
Multiplication: multiply the अंशs together and the हरs together — but factor first and cross-cancel common factors before multiplying to keep numbers small. Example: (x²-1)/(x+3) × (x+3)/(x-1) = (x-1)(x+1)(x+3) / [(x+3)(x-1)] = (x+1), with restrictions x ≠ ±1, x ≠ -3.
Division: multiply the first fraction by the reciprocal of the second (flip the second fraction). Then proceed exactly like multiplication. Remember: the अंश of the original divisor also becomes a हर after the flip, so it contributes new domain restrictions.
Domain Restrictions Explained
The domain of a rational expression is the set of all x-values for which the expression is defined. Any value that makes any हर in the problem zero must be excluded — even if it is cancelled during simplification. This is because the original expression was undefined at that point before simplification occurred.
To find restrictions: set each हर equal to zero and solve. List every solution as an excluded value using "x ≠ ..." notation.