Multiplying and Dividing Rational Expressions Examples in Math

Start with the recap, study the fully worked examples, then use the practice problems to check your understanding of Multiplying and Dividing Rational Expressions.

This page combines explanation, solved examples, and follow-up practice so you can move from recognition to confident problem-solving in Math.

Concept Recap

Multiplying rational expressions by multiplying numerators together and denominators together (after factoring and canceling). Dividing by multiplying by the reciprocal of the divisor.

It works exactly like multiplying and dividing numeric fractions. To multiply: factor everything, cancel common factors across any numerator and any denominator, then multiply across. To divide: flip the second fraction and multiply. abรทcd=abโ‹…dc\frac{a}{b} \div \frac{c}{d} = \frac{a}{b} \cdot \frac{d}{c}.

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How to Use These Examples

  • Read the first worked example with the solution open so the structure is clear.
  • Try the practice problems before revealing each solution.
  • Use the related concepts and background knowledge badges if you feel stuck.

What to Focus On

Core idea: Treat polynomial fractions like numeric fractions: multiply straight across after canceling, and divide by multiplying by the reciprocal.

Common stuck point: The procedure for multiplying and dividing rational expressions is the easy part; the trap is flipping the wrong fraction. Asking "Are the fractions joined by ร—\times or รท\div (so I cancel and multiply across) rather than ++ or โˆ’-?" first is what keeps a correct-looking calculation from being attached to the wrong concept.

Sense of Study hint: Ask: Are the fractions joined by ร—\times or รท\div (so I cancel and multiply across) rather than ++ or โˆ’-?

Worked Examples

Example 1

medium
Multiply x2โˆ’1x+3โ‹…x+3x+1\frac{x^2 - 1}{x + 3} \cdot \frac{x + 3}{x + 1}.

Answer

xโˆ’1x - 1, xโ‰ โˆ’3,โˆ’1x \neq -3, -1

First step

1
Step 1: Factor: (x+1)(xโˆ’1)x+3โ‹…x+3x+1\frac{(x+1)(x-1)}{x+3} \cdot \frac{x+3}{x+1}.

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Example 2

hard
Divide x2โˆ’4x2+xรทxโˆ’2x\frac{x^2 - 4}{x^2 + x} \div \frac{x - 2}{x}.

Example 3

easy
Multiply xโˆ’12โ‹…8xโˆ’1\frac{x-1}{2}\cdot\frac{8}{x-1}, xโ‰ 1x\neq 1.

Example 4

medium
Multiply x2+6x+9x2โˆ’9โ‹…xโˆ’3x+3\frac{x^2 + 6x + 9}{x^2 - 9}\cdot\frac{x-3}{x+3}.

Example 5

medium
Divide x2โˆ’9x2+6x+9รทxโˆ’3x+3\frac{x^2 - 9}{x^2 + 6x + 9}\div\frac{x-3}{x+3}.

Example 6

hard
Simplify 3x2+6xx2+5x+6โ‹…x+33x\frac{3x^2 + 6x}{x^2 + 5x + 6}\cdot\frac{x+3}{3x}, state restrictions.

Practice Problems

Try these problems on your own first, then open the solution to compare your method.

Example 1

easy
Multiply 3xโ‹…x26\frac{3}{x} \cdot \frac{x^2}{6}.

Example 2

medium
Divide x+5xโˆ’1รทx+5x2โˆ’1\frac{x + 5}{x - 1} \div \frac{x + 5}{x^2 - 1}.

Example 3

easy
Multiply 2xโ‹…x3\frac{2}{x}\cdot\frac{x}{3}, xโ‰ 0x\neq0.

Example 4

easy
Multiply 3xโ‹…x26\frac{3}{x}\cdot\frac{x^2}{6}, xโ‰ 0x\neq0.

Example 5

easy
Divide x4รทx2\frac{x}{4}\div\frac{x}{2}, xโ‰ 0x\neq0.

Example 6

easy
Multiply x+12โ‹…4x+1\frac{x + 1}{2}\cdot\frac{4}{x + 1}, xโ‰ โˆ’1x\neq-1.

Example 7

easy
Divide 6xรท3x2\frac{6}{x}\div\frac{3}{x^2}, xโ‰ 0x\neq0.

Example 8

easy
Multiply xx+2โ‹…x+25\frac{x}{x + 2}\cdot\frac{x + 2}{5}, xโ‰ โˆ’2x\neq-2.

Example 9

easy
Multiply 2x3โ‹…94x\frac{2x}{3}\cdot\frac{9}{4x}, xโ‰ 0x\neq0.

Example 10

easy
Divide x+3xรทx+32x\frac{x + 3}{x}\div\frac{x + 3}{2x}, xโ‰ 0,โˆ’3x\neq0,-3.

Example 11

medium
Multiply x2โˆ’4x+3โ‹…x+3xโˆ’2\frac{x^2 - 4}{x + 3}\cdot\frac{x + 3}{x - 2}, state restrictions.

Example 12

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Multiply x2โˆ’9x2+4x+4โ‹…x+2xโˆ’3\frac{x^2 - 9}{x^2 + 4x + 4}\cdot\frac{x + 2}{x - 3}.

Example 13

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Divide x2โˆ’1x+2รทxโˆ’1x+2\frac{x^2 - 1}{x + 2}\div\frac{x - 1}{x + 2}, state restrictions.

Example 14

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Multiply x2+5x+6x2โˆ’4โ‹…xโˆ’2x+3\frac{x^2 + 5x + 6}{x^2 - 4}\cdot\frac{x - 2}{x + 3}.

Example 15

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Divide 2x2+xโˆ’3x2โˆ’1รท2x+3x+1\frac{2x^2 + x - 3}{x^2 - 1}\div\frac{2x + 3}{x + 1}.

Example 16

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Multiply xxโˆ’5โ‹…x2โˆ’25x\frac{x}{x - 5}\cdot\frac{x^2 - 25}{x}, xโ‰ 0,5x\neq0,5.

Example 17

medium
Divide x2โˆ’6x+9x+1รทxโˆ’3x2โˆ’1\frac{x^2 - 6x + 9}{x + 1}\div\frac{x - 3}{x^2 - 1}.

Example 18

medium
Divide x2โˆ’4x+1รทx+2x2โˆ’1\frac{x^2 - 4}{x + 1}\div\frac{x + 2}{x^2 - 1}.

Example 19

medium
Multiply x2+2xx2โˆ’9โ‹…xโˆ’3x\frac{x^2 + 2x}{x^2 - 9}\cdot\frac{x - 3}{x}, xโ‰ 0,ยฑ3x\neq0,\pm3.

Example 20

challenge
Multiply x2โˆ’xโˆ’6x2+2xโˆ’8โ‹…x2+5x+4x2โˆ’9\frac{x^2 - x - 6}{x^2 + 2x - 8}\cdot\frac{x^2 + 5x + 4}{x^2 - 9}.

Example 21

challenge
Divide x3โˆ’8x2โˆ’4รทx2+2x+4x+2\frac{x^3 - 8}{x^2 - 4}\div\frac{x^2 + 2x + 4}{x + 2}, state restrictions.

Example 22

challenge
Multiply 2x2โˆ’3xโˆ’2x2โˆ’4โ‹…x+22x+1\frac{2x^2 - 3x - 2}{x^2 - 4}\cdot\frac{x + 2}{2x + 1}, state restrictions.

Example 23

easy
Multiply 5xโ‹…x10\frac{5}{x}\cdot\frac{x}{10}, xโ‰ 0x\neq 0.

Example 24

easy
Multiply xx+1โ‹…x+1x2\frac{x}{x+1}\cdot\frac{x+1}{x^2}, xโ‰ 0,โˆ’1x\neq 0,-1.

Example 25

easy
Divide x6รท13\frac{x}{6}\div\frac{1}{3}, xx any real.

Example 26

easy
Divide 5x2รทx4\frac{5x}{2}\div\frac{x}{4}, xโ‰ 0x\neq 0.

Example 27

medium
Multiply x2+3xx2โˆ’9โ‹…xโˆ’3x\frac{x^2 + 3x}{x^2 - 9}\cdot\frac{x-3}{x}, xโ‰ 0,ยฑ3x\neq 0,\pm 3.

Example 28

medium
Multiply x2โˆ’1x+3โ‹…x+3xโˆ’1\frac{x^2 - 1}{x+3}\cdot\frac{x+3}{x-1}, state the restrictions.

Example 29

medium
Divide x2โˆ’4x+5รทxโˆ’2x+5\frac{x^2 - 4}{x+5}\div\frac{x-2}{x+5}.

Example 30

medium
Divide x2+7x+12x+2รทx+3x+2\frac{x^2 + 7x + 12}{x+2}\div\frac{x+3}{x+2}.

Example 31

medium
Multiply x2โˆ’xโˆ’12x+2โ‹…x+2xโˆ’4\frac{x^2 - x - 12}{x+2}\cdot\frac{x+2}{x-4}.

Example 32

medium
Multiply 2x2+4xx2โˆ’1โ‹…xโˆ’12x\frac{2x^2 + 4x}{x^2 - 1}\cdot\frac{x-1}{2x}, xโ‰ 0,ยฑ1x\neq 0,\pm 1.

Example 33

medium
Divide 4x2โˆ’9x2โˆ’4รท2xโˆ’3xโˆ’2\frac{4x^2 - 9}{x^2 - 4}\div\frac{2x-3}{x-2}.

Example 34

hard
Multiply x3+27x2โˆ’9โ‹…xโˆ’3x2โˆ’3x+9\frac{x^3 + 27}{x^2 - 9}\cdot\frac{x-3}{x^2 - 3x + 9}.

Example 35

hard
Divide x2+xโˆ’6x2+4x+4รทxโˆ’2x+2\frac{x^2 + x - 6}{x^2 + 4x + 4}\div\frac{x-2}{x+2}.

Example 36

hard
Multiply x2โˆ’5x+6x2โˆ’2xโˆ’3โ‹…x2โˆ’9x2โˆ’4\frac{x^2 - 5x + 6}{x^2 - 2x - 3}\cdot\frac{x^2 - 9}{x^2 - 4}.

Example 37

hard
Divide x2โˆ’16x2+8x+16รทxโˆ’4x+4\frac{x^2 - 16}{x^2 + 8x + 16}\div\frac{x-4}{x+4}.

Example 38

hard
Multiply 3x2โˆ’12x2+xโˆ’6โ‹…x+36\frac{3x^2 - 12}{x^2 + x - 6}\cdot\frac{x+3}{6}.

Example 39

hard
Divide x2โˆ’7x+10x2โˆ’25รทxโˆ’2x+5\frac{x^2 - 7x + 10}{x^2 - 25}\div\frac{x-2}{x+5}.

Example 40

challenge
Simplify x3โˆ’1x2โˆ’1โ‹…x+1x2+x+1\frac{x^3 - 1}{x^2 - 1}\cdot\frac{x+1}{x^2 + x + 1}, state restrictions.

Example 41

challenge
Simplify 6x2โˆ’xโˆ’12x2+5x+2รท3x+1x+2\frac{6x^2 - x - 1}{2x^2 + 5x + 2}\div\frac{3x+1}{x+2}.

Background Knowledge

These ideas may be useful before you work through the harder examples.

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