Example

Simplifying 10x4x-\frac{10}{x} - \frac{4}{x}

Subtract two fractions that share the variable denominator xx:

10x4x-\frac{10}{x} - \frac{4}{x}

Apply the subtraction rule by combining the numerators over the common denominator:

104x=14x\frac{-10 - 4}{x} = \frac{-14}{x}

Rewrite with the negative sign in front of the fraction rather than in the numerator:

14x-\frac{14}{x}

This example shows that the common-denominator subtraction rule acbc=abc\frac{a}{c} - \frac{b}{c} = \frac{a - b}{c} works identically when the shared denominator is a variable instead of a number. As with numerical fractions, the negative sign can be moved from the numerator to in front of the fraction bar.

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Updated 2026-04-21

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