Пошаговое объяснение:
1) 3х-(х+4)=3х-х-4=2х-4=2×(-7)-4=
= - 14-4= - 18
1) 3х-|х+4|=3×(-7)-|-7+4|=
= - 21-|-3|= - 21-3= - 24
2) |1-2х|-|х|=|1-2×0,7|-|0,7|=
=|1-1,4|-0,7=|-0,4|-0,7=0,4-0,7= - 0,3
3) 4/7-|х-3 5/14|=4/7-|3 13/14-3 5/14|=
=4/7-|8/14|=4/7-|4/7|=4/7-4/7=0
4) |6х+9|+2х=|6×(-7)+9|+2×(-7)=
=|-42+9|-14=|-33|-14=33-14=19
5) |7х-3,6|+|х|=|7×0,7-3,6|+|0,7|=
=|4,9-3,6|+0,7=|1,3|+0,7=1,3+0,7=2
6) |3-4х|+|-у|=|3-4×2,1|+|-0,4|=
=|3-8,4|+0,4=|-5,4|+0,4=5,4+0,4=5,8
7) 3|х-1|-2|3-у|=3|0,7-1|-2|3-1,7|=
=3|-0,3|-2|1,3|=3×0,3-2×1,3=
=0,9-2,6= - 1,7
8) 5х+|1+8х|=5×(-1,4)+|1+8×(-1,4)|=
= - 7+|1-11,2|= - 7+|-10,2|= - 7+10,2=3,2
9) |2х-9|+3|=|2×(-4)-9|+3|=не поятно
715200/60/60=198.667 часов