A rational equation is an equation that contains at least one fraction whose numerator and denominator are polynomials. Rational equations can be solved by reducing the fractions to a common denominator and then solving the equality of the numerators. When solving a rational equation, it is important to note cases where indeterminate forms like 0/0 or 1/0 may arise. Multiplying both sides of the equation by the least common denominator (LCD) is a common method to clear fractions. However, care must be taken to ensure that the denominator is not zero by making note of restrictions and checking that no solution makes a denominator zero in the original equation. Rational equations are sometimes expressed using negative exponents.