1- Effectuez: $\frac{ab}{c}\cdot\frac{3c^2}{a^2}\div\frac{a^2b^3}{9c}$
$\frac{ab^4}{3}$	$\frac{27abc^3}{a^4b^3c}$	$\frac{27c^2}{a^3b^2}$>

2- Effectuez: $\frac{42a^3bc^2}{x}\div\frac{7ab^3c}{x^3}$
$\frac{294a^4b^4c^3}{x^4}$	$\frac{42a^3bc^2x^3}{7ab^3cx}$	$\frac{6a^2cx^2}{b^2}$

3- Effectuez: $\frac{16x^6y^2z}{ab^3}\cdot\frac{7a^2b}{32x^4z}$
$\frac{7x^2y^2a}{2b^2}$	$\frac{512x^{10}y^2z^2}{7a^3b4}$	$\frac{112a^2bx^6y^2z}{32ab^3x^4z}$

4- Effectuez: $\frac{\frac{(n+1)(n+2)^3}{(n-1)^2}}{\frac{(n+1)^3(n+2)}{(n-1)^2}}$
$\frac{(n+1)^4(n+2)^2}{(n-1)^4}$	$\frac{(n+2)^2}{(n+1)^2}$	$\frac{(n+1)(n+2)^3(n-1)^2}{(n-1)^2(n+1)^3(n+2)}$

5- Effectuez (voir addition et soustraction): $\frac{\frac{1}{x^2}-1}{\frac{1}{x}+1}$
$\frac{1-x}{x}$	$\frac{1-x^2}{x(1+x)}$	$\frac{(1-x^2)(1+x)}{x^3}$