1) (3x/4y):(9x^2/8) = (3x/4y) * (8/9x^2) = (3x*8)/(4y*9x^2) = 2/3xy
2) (10/11a^2):(5c/22ab) = (10/11a^2)*(22ab/5c) = (10* 22ab)/(11a^2 * 5c) = 4b/ac
3) (13a/4b^2):(26ab) = (13a)/(4b^2*26ab) = 1/8b^3
4) (8x/(y-1)):(4/3(y-1) = (8x/(y-1))*(3(y-1)/4) = (8x*3*(y-1))/((y-1)*4) = 6
5) ((2x-4)/5y):((x-2)/10y^3) = ((2x-4)/5y)*(10y^3/(x-2)) = (2*(x-2) *10y^3)/ (5y*(x-2)) = 4y^2