Răspuns:
1) 4,2x+ 3,4x=19
7,6=19
x=2,5
2)0,5×(2,7+x)=7,25
2,7+x=14,5
x=14,5-2,7
x=11,8
3)2,15x+ 6,14=7,43
2,15x=7,43-6,14
2,15x= 1,29
x=0,6
4) 1,35x-2,42:4=6,28
1,35x-0,605=6, 28
1,35x=6,28+0,605
1,35x=6,885
x=5,1
