X-18(1/5)=2(7/15) (x-2(7/8)+3(5/6)=4(2/3)

X - 18 1/5 = 2 7/15,
х = 2 7/15 + 18 1/5,
х = 2 7/15 + 18 3/15,
х = 20 10/15,
х = 20 2/3,

x - 2 7/8 + 3 5/6 = 4 2/3,
х = 4 2/3 + 2 7/8 - 3 5/6,
х = 4 16/24 + 2 21/24 - 3 15/18,
х = 3 22/18 = 4 4/18,
х = 4 2/9