Ответ:

а) \(\frac{(2a-2b)^2}{a-b}=\frac{4(a-b)^2}{a-b}=4(a-b)\).

б) \(\frac{(3c+9d)^2}{c+3d}=\frac{9(c+3d)^2}{c+3d}=9(c+3d)\).

в) \(\frac{(3x+6y)^2}{5x+10y}=\frac{9(x+2y)^2}{5(x+2y)}=\frac{9(x+2y)}{5}\).

г) \(\frac{4x^2-y^2}{(10x+5y)^2}=\frac{(2x-y)(2x+y)}{25(2x+y)^2}=\frac{2x-y}{25(2x+y)}\).