Question

7,8a+2,3a-5a a=6

2(0,3b+5)+1,4b b=4

6(a+1,5)-2,8a a=1,5

4(b+0,8)+1,7b b=2,3

Answer 1

1) 7.8a+2.3a-5a=5.1a
a=6
5.1a*6=30.6
2) 2(0.3b+5)+1.4b=0.6b+10+1.4b=2b+10
b=4
2b+10=8+10=18
3) 6(a+5)-2.8a=6a+30-2.8a=3.2a+30
a=1.5
3.2a+30=4.8+30=34.8
4) 4(b+0.8)+1.7b=4b+3.2+1.7b=5.7b+3.2
b=2.3
5.7b+3.2=13.11+3.2=16.41

Answer 2

1)a*(7,8+2,3)-5a= 10,1a-5a=5,1a*6=30,6

2)(при умножении на скобку получилось )=(0,6b+10)+1,4b=10,6b+1,4b=12b=12*4=48