15+х=800:20; 15+х=40; Х=40-15. Х=25. Проверка: 15+25=800:20
5,6/3х+12=0,4/3
(5целых 6/10):3*х=(4/10):3
56/(10*3х)=4/30
30х=56:(4/30)=(56*30)/4=1680/4=420
х=420/30=14
1) = 25 - 26 = ( - 1 )
2) = 19 - 48 = ( - 29 )
3) = 60.4 - 70.4 = ( - 10 )
4)
1) 3 1\3 + 1 2\3 = 4 3\3 = 5
2) 2 3\5 + 2 2\5 = 4 5\5 = 5
3) 5 + 3 2\15 = 8 2\15
4) 5 - 8 2\15 = ( - 3 2\15 ) ( ответ )