Đề bài

Tính:

a) $\frac{{{x^2} - 5x}}{{4{y^2}}}:\frac{{5x}}{{2y}}$;                                          

b) $\frac{{{x^2} - 1}}{y}:\frac{{x + 1}}{{{y^2}}}$;

c) $\left( {{x^2} - 2xy} \right):\frac{{5x - 10y}}{x}$;                                  

d) $\frac{{{x^2} - x}}{{x - y}}:\left( {{x^2} + xy} \right)$;

e) $\left( {16 - {x^2}} \right):\left( {{x^2} - 4x} \right)$;                             

g) $\frac{{4{y^2} - {x^2}}}{{{x^2} + 2xy + {y^2}}}:\frac{{x - 2y}}{{2{x^2} + 2xy}}$.