Х×2 1/2: 1 1/5 -7/18=1 5/6
Х×2 1/2: 1 1/5 -7/18=1 5/6; 5/2х*5/11=11/6+7/18; 25/22х=33/18+7/18; Х=40/18*22/25; Х=88/45; Х=1ц 43/45