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分式运算计算题专练

分式运算计算题专练 完成时间:_______ 分钟 得分:_______ 一、分式的化简(共8题) 请将下列分式化为最简分式: 1. 6 a 2 b 9 a b 2 \frac{6a^2b}{9ab^2} 9 a b 2 6 a 2 b 2. x 2 − 9 x + 3 \frac{x^2 - 9}{x + 3} x + 3 x 2 − 9 3. a 2 −

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分式运算计算题专练


完成时间:_______ 分钟 得分:_______


一、分式的化简(共8题)

请将下列分式化为最简分式:


1. 6a2b9ab2\frac{6a^2b}{9ab^2}

2. x29x+3\frac{x^2 - 9}{x + 3}

3. a24a+4a24\frac{a^2 - 4a + 4}{a^2 - 4}

4. 2m28m24m+4\frac{2m^2 - 8}{m^2 - 4m + 4}

5. 3x212x24x+4\frac{3x^2 - 12}{x^2 - 4x + 4}

6. a22ab+b2a2b2\frac{a^2 - 2ab + b^2}{a^2 - b^2}

7. 4x2x24x+4\frac{4 - x^2}{x^2 - 4x + 4}

8. x25x+6x23x\frac{x^2 - 5x + 6}{x^2 - 3x}



二、分式的乘除(共8题)

请计算下列各题:


1. 3a4b×8b29a2\frac{3a}{4b} \times \frac{8b^2}{9a^2}

2. x2y÷xy2\frac{x^2}{y} \div \frac{x}{y^2}

3. a21a×a2a+1\frac{a^2 - 1}{a} \times \frac{a^2}{a + 1}

4. m24m22m÷m+2m\frac{m^2 - 4}{m^2 - 2m} \div \frac{m + 2}{m}

5. x24x+4x24×x+2x2\frac{x^2 - 4x + 4}{x^2 - 4} \times \frac{x + 2}{x - 2}

6. a29a2+3a÷a3a\frac{a^2 - 9}{a^2 + 3a} \div \frac{a - 3}{a}

7. 2xx21×x2+2x+14x2\frac{2x}{x^2 - 1} \times \frac{x^2 + 2x + 1}{4x^2}

8. a22ab+b2a2b2÷aba+b\frac{a^2 - 2ab + b^2}{a^2 - b^2} \div \frac{a - b}{a + b}



三、分式的加减(共8题)

请计算下列各题:


1. 2a+3a\frac{2}{a} + \frac{3}{a}

2. 5x2x\frac{5}{x} - \frac{2}{x}

3. 1a+1b\frac{1}{a} + \frac{1}{b}

4. 3x2y\frac{3}{x} - \frac{2}{y}

5. 2a+1+3a+1\frac{2}{a + 1} + \frac{3}{a + 1}

6. xx11x1\frac{x}{x - 1} - \frac{1}{x - 1}

7. 1x+2+1x2\frac{1}{x + 2} + \frac{1}{x - 2}

8. 2a11a+1\frac{2}{a - 1} - \frac{1}{a + 1}



四、分式的混合运算(共6题)

请计算下列各题:


1. ab×ba+1a\frac{a}{b} \times \frac{b}{a} + \frac{1}{a}

2. (xy)2÷xy2\left( \frac{x}{y} \right)^2 \div \frac{x}{y^2}

3. 1a+ab×ba2\frac{1}{a} + \frac{a}{b} \times \frac{b}{a^2}

4. (1x1y)×xyyx\left( \frac{1}{x} - \frac{1}{y} \right) \times \frac{xy}{y - x}

5. xx1xx+1\frac{x}{x - 1} - \frac{x}{x + 1}

6. (aa+1+1)÷2a+1a21\left( \frac{a}{a + 1} + 1 \right) \div \frac{2a + 1}{a^2 - 1}



五、分式的化简求值(共4题)

请先化简,再求值:

1. 先化简,再求值:x21x22x+1÷x+1x1\frac{x^2 - 1}{x^2 - 2x + 1} \div \frac{x + 1}{x - 1},其中 x=3x = 3

答:________________________________________


2. 先化简,再求值:a24a24a+4×a2a+2\frac{a^2 - 4}{a^2 - 4a + 4} \times \frac{a - 2}{a + 2},其中 a=4a = 4

答:________________________________________


3. 先化简,再求值:1x+1+1x1\frac{1}{x + 1} + \frac{1}{x - 1},其中 x=2x = 2

答:________________________________________


4. 先化简,再求值:(xx2xx+2)÷4xx24\left( \frac{x}{x - 2} - \frac{x}{x + 2} \right) \div \frac{4x}{x^2 - 4},其中 x=1x = 1

答:________________________________________

参考答案

一、分式的化简

1. 2a3b\frac{2a}{3b}

2. x3x - 3(提示:(x+3)(x3)x+3=x3\frac{(x + 3)(x - 3)}{x + 3} = x - 3

3. a2a+2\frac{a - 2}{a + 2}(提示:(a2)2(a+2)(a2)=a2a+2\frac{(a - 2)^2}{(a + 2)(a - 2)} = \frac{a - 2}{a + 2}

4. 2(m+2)m2\frac{2(m + 2)}{m - 2}(提示:2(m24)(m2)2=2(m+2)(m2)(m2)2=2(m+2)m2\frac{2(m^2 - 4)}{(m - 2)^2} = \frac{2(m + 2)(m - 2)}{(m - 2)^2} = \frac{2(m + 2)}{m - 2}

5. 3(x+2)x2\frac{3(x + 2)}{x - 2}(提示:3(x24)(x2)2=3(x+2)(x2)(x2)2=3(x+2)x2\frac{3(x^2 - 4)}{(x - 2)^2} = \frac{3(x + 2)(x - 2)}{(x - 2)^2} = \frac{3(x + 2)}{x - 2}

6. aba+b\frac{a - b}{a + b}(提示:(ab)2(a+b)(ab)=aba+b\frac{(a - b)^2}{(a + b)(a - b)} = \frac{a - b}{a + b}

7. x+2x2-\frac{x + 2}{x - 2}(提示:(x24)(x2)2=(x+2)(x2)(x2)2=x+2x2\frac{-(x^2 - 4)}{(x - 2)^2} = \frac{-(x + 2)(x - 2)}{(x - 2)^2} = -\frac{x + 2}{x - 2}

8. x2x\frac{x - 2}{x}(提示:(x2)(x3)x(x3)=x2x\frac{(x - 2)(x - 3)}{x(x - 3)} = \frac{x - 2}{x}

二、分式的乘除

1. 2b3a\frac{2b}{3a}

2. xyxy(提示:x2y×y2x=xy\frac{x^2}{y} \times \frac{y^2}{x} = xy

3. a1a - 1(提示:(a+1)(a1)a×a2a+1=a(a1)\frac{(a + 1)(a - 1)}{a} \times \frac{a^2}{a + 1} = a(a - 1),注意约分后为 a1a - 1,此处原式化简为 a(a1)a(a - 1),但若题目要求最简结果,应为 a(a1)a(a - 1)。更正:(a+1)(a1)aa2a+1=a(a1)\frac{(a+1)(a-1)}{a} \cdot \frac{a^2}{a+1} = a(a-1)

4. 11(提示:(m+2)(m2)m(m2)×mm+2=1\frac{(m + 2)(m - 2)}{m(m - 2)} \times \frac{m}{m + 2} = 1

5. 11(提示:(x2)2(x+2)(x2)×x+2x2=1\frac{(x - 2)^2}{(x + 2)(x - 2)} \times \frac{x + 2}{x - 2} = 1

6. 11(提示:(a+3)(a3)a(a+3)×aa3=1\frac{(a + 3)(a - 3)}{a(a + 3)} \times \frac{a}{a - 3} = 1

7. x+12x(x1)\frac{x + 1}{2x(x - 1)}(提示:2x(x+1)(x1)×(x+1)24x2=x+12x(x1)\frac{2x}{(x + 1)(x - 1)} \times \frac{(x + 1)^2}{4x^2} = \frac{x + 1}{2x(x - 1)}

8. 11(提示:(ab)2(a+b)(ab)×a+bab=1\frac{(a - b)^2}{(a + b)(a - b)} \times \frac{a + b}{a - b} = 1

三、分式的加减

1. 5a\frac{5}{a}

2. 3x\frac{3}{x}

3. a+bab\frac{a + b}{ab}

4. 3y2xxy\frac{3y - 2x}{xy}

5. 5a+1\frac{5}{a + 1}

6. 11(提示:x1x1=1\frac{x - 1}{x - 1} = 1

7. 2xx24\frac{2x}{x^2 - 4}(提示:x2+x+2(x+2)(x2)=2xx24\frac{x - 2 + x + 2}{(x + 2)(x - 2)} = \frac{2x}{x^2 - 4}

8. a+3a21\frac{a + 3}{a^2 - 1}(提示:2(a+1)(a1)(a1)(a+1)=2a+2a+1a21=a+3a21\frac{2(a + 1) - (a - 1)}{(a - 1)(a + 1)} = \frac{2a + 2 - a + 1}{a^2 - 1} = \frac{a + 3}{a^2 - 1}

四、分式的混合运算

1. 1+1a=a+1a1 + \frac{1}{a} = \frac{a + 1}{a}

2. xx(提示:x2y2×y2x=x\frac{x^2}{y^2} \times \frac{y^2}{x} = x

3. 2a\frac{2}{a}(提示:1a+ab×ba2=1a+1a=2a\frac{1}{a} + \frac{a}{b} \times \frac{b}{a^2} = \frac{1}{a} + \frac{1}{a} = \frac{2}{a}

4. 1-1(提示:yxxy×xyyx=1\frac{y - x}{xy} \times \frac{xy}{y - x} = 1,注意 1x1y=yxxy\frac{1}{x} - \frac{1}{y} = \frac{y - x}{xy},所以结果为 11。更正:yxxyxyyx=1\frac{y-x}{xy} \cdot \frac{xy}{y-x} = 1

5. 2xx21\frac{2x}{x^2 - 1}(提示:x(x+1)x(x1)(x1)(x+1)=x2+xx2+xx21=2xx21\frac{x(x + 1) - x(x - 1)}{(x - 1)(x + 1)} = \frac{x^2 + x - x^2 + x}{x^2 - 1} = \frac{2x}{x^2 - 1}

6. a1a - 1(提示:a+a+1a+1×(a+1)(a1)2a+1=2a+1a+1×(a+1)(a1)2a+1=a1\frac{a + a + 1}{a + 1} \times \frac{(a + 1)(a - 1)}{2a + 1} = \frac{2a + 1}{a + 1} \times \frac{(a + 1)(a - 1)}{2a + 1} = a - 1

五、分式的化简求值

1. 化简:(x+1)(x1)(x1)2×x1x+1=1\frac{(x + 1)(x - 1)}{(x - 1)^2} \times \frac{x - 1}{x + 1} = 1。当 x=3x = 3 时,原式 =1= 1

2. 化简:(a+2)(a2)(a2)2×a2a+2=1\frac{(a + 2)(a - 2)}{(a - 2)^2} \times \frac{a - 2}{a + 2} = 1。当 a=4a = 4 时,原式 =1= 1

3. 化简:x1+x+1(x+1)(x1)=2xx21\frac{x - 1 + x + 1}{(x + 1)(x - 1)} = \frac{2x}{x^2 - 1}。当 x=2x = 2 时,原式 =441=43= \frac{4}{4 - 1} = \frac{4}{3}

4. 化简:x(x+2)x(x2)(x2)(x+2)×x244x=4x(x2)(x+2)×(x2)(x+2)4x=1\frac{x(x + 2) - x(x - 2)}{(x - 2)(x + 2)} \times \frac{x^2 - 4}{4x} = \frac{4x}{(x - 2)(x + 2)} \times \frac{(x - 2)(x + 2)}{4x} = 1。当 x=1x = 1 时,原式 =1= 1