第76页 - 江苏版启东中学作业本八年级数学（上下册）

C

B

C

D

$6x²y²$

$2x(x+1)(x-1)$

$10a²b²c$

$2a²$

$5bc$

$ab²$

$\frac {x+1}{x^2-1}$

$\frac {x-1}{x^2-1}$

$\frac 1{x^2-1}$

解：$\frac {2}{xy}=\frac {4}{2xy}$，$\frac {x}{2y}=\frac {x^2}{2xy}$

解：$\frac {5}{-4ab^2}=-\frac {25a}{20a^2b^2}$，$\frac {4}{5a^2b}=\frac {16b}{20a^2b^2}$

解：$\frac {x}{a(x-y)}=\frac {bx}{ab(x-y)}$，$\frac {y}{b(y-x)}= -\frac {ay}{ab(x-y)}$

解：$\frac {a}{(x-y)^2}= \frac {a(x+y)}{(x-y)^2(x+y)}$，

$\frac {b}{(x-y)(x+y)}=\frac {b(x-y)}{(x-y)^2(x+y)}$