第6页 - 江苏版启东中学作业本八年级数学（上下册）

$=\frac {ab^2}{6ac}$

$=\frac {b^2}{6c} $

$=\frac {3xy^3}{4z^2}· (-\frac {8z^2}{y})$

$=-\frac {24xy^2z^2}{4z^2y}$

$=-6xy$

$=\frac {(-2m)^3}{(3n)^3}$

$=-\frac {8\ \mathrm {m^3}}{27n^6}$

$=\frac 2{(x+1)(x-1)}· (x-1)$

$=\frac 2{x+1}$

$=\frac {(x+1)(x-1)}{x(x+2)}· \frac x{x-1}$

$=\frac {x+1}{x+2}$

$=\frac {(x+1)^2}{(x+1)(x-1)}· \frac 1{x+1}$

$=\frac 1{x-1}$

$=\frac {(x+2)(x-2)}{4x^2y}· \frac {6x^3y}{3(x+2)}$

$=\frac {x(x-2)}2$

$=\frac {x}{(x+1)(x-1)}· \frac {x(x+1)}{x²}$

$=\frac {1}{x-1}$

$=\frac {(x+1)^2}{(x+1)(x-1)}· \frac {x(x-1)}{x+1}$

$=x$

$=\frac {a+3}{1-a}· \frac {(a-1)^2}{a(a+3)}$

$=\frac {a+3}{1-a}· \frac {(1-a)^2}{a(a+3)}$

$=\frac {1-a}{a}$

$=\frac {\mathrm {m^2}}{n^2}· \frac {n}{m}· (-\frac {n^2}{m})$

$=\frac {m}{n}· (-\frac {n^2}{m})$

$=-n$

$=\frac {ab^2}{2c^2}· \frac {4cd}{-3a^2b^2}· \frac {-3}{2d}$

$=\frac 1{ac}$

$=-\frac {a-1}{a+2}· \frac {(a+2)(a-2)}{(a-1)^2}· (a+1)(a-1)$

$= -(a-2)(a+1)$

$=-a^2+a+2$

$ =-x(x-y)· \frac {xy}{(x-y)^2}· \frac {x-y}{x^2}$

$=-y$