1)7,2+1,6x=1-1,5x
7,2-1=-1,5x-1,6x
6,2=-3,1x
x=-2
2)<span>0.5*(x+3)=0.8*(10-x)
</span>0,5x+1,5=8-0,8x
0,5x+0,8x=8-1,5
1,3x=6,5
x=5
15+13=28
28-8=20
20+34=54
54-21=33
33+123=156
7*5=105 (съели)
156-105=51 (осталось)
40÷6=6 4 ост.
60÷9=6 6ост.
80÷9=8 8ост.
(-1 1/9)(1 3/5-1/4)+2/5=119/180
1) 1 1/9 * 1 3/5 + 1/4*1 1/9=88/45+11/36=
=3168/1620+495/1620=3663/1620= 2 423/1620
2) 423/1620+2/5=423/1620+648/1620=1071/1620=357/540=119/180
1409кг-628кг=781кг=7ц81кг