2)3a+5=8a-15
3a – 8a = – 15 – 5
-5a = -20
a = 4
3)0,4x+0,3x=0,84x+1,12
0,4x + 0,3x – 0,84x = 1,12
-0.14x = 1.12
x = -8
4)5·(x+1,2)=12,5
5x + 6 = 12.5
5x = 12,5 – 6
5x = 6.5
x = 1.3
2)3a+5=8a-15
3a – 8a = – 15 – 5
-5a = -20
a = 4
3)0,4x+0,3x=0,84x+1,12
0,4x + 0,3x – 0,84x = 1,12
-0.14x = 1.12
x = -8
4)5·(x+1,2)=12,5
5x + 6 = 12.5
5x = 12,5 – 6
5x = 6.5
x = 1.3