x/2 : 5/7 = x/3 * 5/4 + 1/5

x/2 : 5/7 - x/3 * 5/4 = 1/5

x/2 * 7/5 - x/3 * 5/4 = 1/5

7x/10 - 5x/12 = 1/5

76x/106 - 55x/125 = 1/5

42x/60 - 25x/60 = 1/5

(42x-25x)/60 = 1/5

17x/60 = 1/5

17x = 60/5

x = 60/(5*17)

x = 12/(1*17)

x = 12/17