39(х+5)+7х=(раскроем скобки)=39х+195+7х=(приведем подобные)=46х+195; подставим х=4: 46*4+195=379
[-75+45+(-30)] : (-15) = 2
1) -75 + 45 = -30
2) -30 + (-30) = -60
3) -60 : (-15) = 2
1) 7/20 * 9 = 63/20
2) 12 * 7/36 = 7/3
3) 18/15 : 4 = 9/30
4) 3/5 : 41/2 = 6/205
5) 63/20 + 7/3 = 189/60 + 140/60 = 329/60
6) 329/60 + 9/30 = 329/60 + 18/60 = 347/60
7) 347/60 + 6/205 = (347 * 205)/12300 + (6 * 60)/12300 = 71135/12300 + 360/12300 = 71495/12300 =
= 5целых 1999/2460