45+(х-37)=75
45+х-37=75
х=75-45+37
х=67
х+374=679
х=679-374
х=305
( 1 - 3/4) * (4/5 - 3/4) =
= 1/4 * (16/20 - 15/20) =
= 1/4 * 1/20 = 1/80
14 * (1/2 + 1/3 + 1/4) =
= 14 * ( 6/12 + 4/12 + 3/12) =
= 14/1 * 13/12 =
= (7 * 13)/ (1* 6) = 91/6 =
= 15 целых 1/6
1/3 * 6/7 - 1/7 * 3/4 =
= 2/7 - 3/28 =
= 8/28 - 3/28 =
= 5/28
1)0.5
2)440000
3)2.8е в -7
4)0.0002432
1800 : 2 =900(км/ч)-скорость самолёта на всём пути