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1. 约分：(1)$\frac {5ab}{20a^{2}b}=$____；(2)$\frac {x^{2}-9}{x^{2}-6x+9}=$____.
答案
(1) $\frac{1}{4a}$ (2) $\frac{x + 3}{x - 3}$
2. 计算：$\frac {a^{2}}{4b}\cdot (\frac {6b}{a})^{2}=$____.
答案
$9b$
3. 若$\frac {1}{a}-\frac {1}{b}=1$，则$\frac {ab}{a-b}$的值是____.
答案
$-1$
4. 若$\frac {M}{4-x^{2}}=\frac {x}{2-x}$，则$M=$____.
答案
$x^{2}+2x$
5. 若分式$A=\frac {4}{x^{2}-4},B=\frac {1}{x+2}+\frac {1}{2-x}$，则A与B的关系是____.
答案
$A + B = 0$
6. 下列分式是最简分式的是( ).
A. $\frac {a-b}{b-a}$
B. $\frac {x^{2}}{x-1}$
C. $\frac {x^{2}-4}{x-2}$
D. $\frac {m+2}{m^{2}+m-2}$
A. $\frac {a-b}{b-a}$
B. $\frac {x^{2}}{x-1}$
C. $\frac {x^{2}-4}{x-2}$
D. $\frac {m+2}{m^{2}+m-2}$
答案
B
7. 下列各式计算或化简正确的是( ).
A. $\frac {a^{2}-2ab+b^{2}}{b-a}=a-b$
B. $\frac {x^{2}+2xy+y^{2}}{(x+y)^{3}}=x+y$
C. $(\frac {x^{3}}{y^{4}})^{2}=\frac {x^{5}}{y^{6}}$
D. $-\frac {1}{-x+y}=\frac {1}{x-y}$
A. $\frac {a^{2}-2ab+b^{2}}{b-a}=a-b$
B. $\frac {x^{2}+2xy+y^{2}}{(x+y)^{3}}=x+y$
C. $(\frac {x^{3}}{y^{4}})^{2}=\frac {x^{5}}{y^{6}}$
D. $-\frac {1}{-x+y}=\frac {1}{x-y}$
答案
D
8. 化简$\frac {x^{2}}{x-y}+\frac {y^{2}}{y-x}$的结果是( ).
A. $-x-y$
B. $y-x$
C. $x-y$
D. $x+y$
A. $-x-y$
B. $y-x$
C. $x-y$
D. $x+y$
答案
D
9. 若$\frac {x}{x-y}=\frac {1}{2}$，则$\frac {x}{y}$等于( ).
A. $\frac {1}{2}$
B. $-1$
C. $1$
D. $-\frac {1}{2}$
A. $\frac {1}{2}$
B. $-1$
C. $1$
D. $-\frac {1}{2}$
答案
B
