Practice Adding and Subtracting Rational Expressions in Math

Use these practice problems to test your method after reviewing the concept explanation and worked examples.

Quick Recap

Adding or subtracting rational expressions by finding a least common denominator (LCD), rewriting each fraction with the LCD, then combining the numerators over the common denominator.

Just like 13+14\frac{1}{3} + \frac{1}{4} requires a common denominator of 12, adding 2x+1+3xโˆ’2\frac{2}{x+1} + \frac{3}{x-2} requires the LCD (x+1)(xโˆ’2)(x+1)(x-2). Rewrite each fraction so both have the same denominator, then add the numerators. The process mirrors numeric fractions but with polynomial denominators.

Showing a random 20 of 50 problems.

Example 1

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Add 5x+3xโˆ’2\frac{5}{x} + \frac{3}{x - 2}, xโ‰ 0,2x\neq0,2.

Example 2

hard
Combine xx2โˆ’9+1xโˆ’3โˆ’1x+3\frac{x}{x^2-9}+\frac{1}{x-3}-\frac{1}{x+3} for xโ‰ ยฑ3x\ne\pm 3.

Example 3

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Add 2x+1+3xโˆ’2\frac{2}{x + 1} + \frac{3}{x - 2}, xโ‰ โˆ’1,2x\neq-1,2.

Example 4

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Subtract x+1xโˆ’xโˆ’1x+1\frac{x + 1}{x} - \frac{x - 1}{x + 1}, xโ‰ 0,โˆ’1x\neq0,-1.

Example 5

challenge
Subtract xx2โˆ’xโˆ’6โˆ’2xโˆ’3\frac{x}{x^2 - x - 6} - \frac{2}{x - 3}, xโ‰ 3,โˆ’2x\neq3,-2.

Example 6

challenge
Add 3xโˆ’2+2x+2+1x2โˆ’4\frac{3}{x - 2} + \frac{2}{x + 2} + \frac{1}{x^2 - 4}, xโ‰ ยฑ2x\neq\pm2.

Example 7

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For what value(s) of xx is 1xโˆ’3+1x+3\frac{1}{x-3}+\frac{1}{x+3} undefined?

Example 8

easy
Add 3x+2x2\frac{3}{x} + \frac{2}{x^2}, xโ‰ 0x\neq0.

Example 9

hard
Find the value of 1xโˆ’2+1x+2\frac{1}{x-2}+\frac{1}{x+2} at x=3x=3.

Example 10

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Subtract 1x+2โˆ’1xโˆ’2\frac{1}{x+2}-\frac{1}{x-2} for xโ‰ ยฑ2x\ne\pm 2.

Example 11

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Add 2xโˆ’1+3x+2\frac{2}{x-1}+\frac{3}{x+2} for xโ‰ 1,โˆ’2x\ne 1,-2.

Example 12

easy
Simplify 2xx+1โˆ’xโˆ’1x+1\frac{2x}{x+1}-\frac{x-1}{x+1} for xโ‰ โˆ’1x\ne -1.

Example 13

hard
Combine 1x+1x+1+1x+2\frac{1}{x}+\frac{1}{x+1}+\frac{1}{x+2} for xโ‰ 0,โˆ’1,โˆ’2x\ne 0,-1,-2.

Example 14

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Add 1x+2x2+3x3\frac{1}{x} + \frac{2}{x^2} + \frac{3}{x^3}, xโ‰ 0x\neq0.

Example 15

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Combine 2x2โˆ’3x3\frac{2}{x^2}-\frac{3}{x^3} for xโ‰ 0x\ne 0.

Example 16

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Add 2x+1+3xโˆ’2\frac{2}{x+1} + \frac{3}{x-2}.

Example 17

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Worked example: combine 3x2โˆ’4+1xโˆ’2\frac{3}{x^2-4}+\frac{1}{x-2} for xโ‰ ยฑ2x\ne\pm 2.

Example 18

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Subtract xxโˆ’3โˆ’3xโˆ’3\frac{x}{x - 3} - \frac{3}{x - 3} and simplify, xโ‰ 3x\neq3.

Example 19

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Subtract 5xโˆ’3โˆ’2x+1\frac{5}{x-3} - \frac{2}{x+1}.

Example 20

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Add xxโˆ’2+2x+2\frac{x}{x-2}+\frac{2}{x+2} for xโ‰ ยฑ2x\ne\pm 2.