19/9*3/7+21/4*8+
+(82/15*1/41-5/2*4/15)=
19/21+42+(2/15-2/3)=
=42 19/21-8/15=
=42 95/105-56/105=
=42 39/105=42 13/35
45/7*7/9*10/3/1*4/21*4/21=
=50/3*441/16=25*147/8=
=3675/8=459 3/8
А)(х-111)*59=11918
59х-6549=11918
59х=11918-6549
59х=5369
х=91
б)975(y-615)=12675
975у-599325=12675
975у=12675+599325
975у=612300
у=628
<span> </span>
РЕШЕНИЕ
∠2 = 180 - ∠1 - ∠3 = 180° - 57° - 49° = 74° - ОТВЕТ