-5.7:(-19)-0.8*(-4)+2.7:0.3=12.5
Решаем по действиям:
1. 5.7:(-19)=-5.7/19
2. 5.7/19=0.3
5.70|1_9_ _
5_7_ |0.3
0
3. -(-0.3)=0.3
4. 0.8*(-4)=-0.8*4
5. 0.8*4=3.2
X0.8
_ _4_ _
3.2
6. 0.3-(-3.2)=0.3+3.2
7. 0.3+3.2=3.5
+0.3
_3_._2_
3.5
8. 2.7:0.3=9
2.70|0_._3_ _
2_7_ |9
0
9. 3.5+9=12.5
+3.5
_9_._0_
12.5
Ответ: 12,5