2/3-8/23*(3/4+1ц1/6) 2) 5/26-1ц1/5*1ц1/9+1ц5/7: 1ц1/7

1) 2/3-8/23*(3/4+1.1/6)=2/3-8/23*3/4+8/23*7/6=2/3-2/23*3+4/23*7/3=2/3-6/23+28/69=2/3-(18+28)/69=2/3-46/69=(46-46)/69=0/69=0;
2) 5/26-6/5*10/9+12/7:8/7=5/26-2*2/3+12/8=5/26-4/3+2/8=5/26-(32+6)/24=5/26-38/24=5/26-19/12=5/26-1.7/12=-1(60-182)/312=-2.122/312=-2.61/156;