0,5(2,7+a)=7,25
2,7+a=7,25/,05
2,7+a=14,5
a=14,5-2,7
a=11,8
21,5a+6,14=7,43
21,5a=7,43-6,14
21,5a=1,29
a=1,29/21,5
a=0,05
1,35a-2,42x4=6,28
1,35a-9,68=6,28
1,35a=6,28+9,68
1,35a=15,96
a=15,96/1,35
a=11,0(814)
2,7x5,3-1,3a=11,97
14,31-1,3a=11,97
-1,3a=11,97-14,31
-1,3a=-2,34 inmultim cu -1
a=2,34/1,3
a=1,8
impartirea cu 22 zecimale fa-o tu si pune mana si invata ca sunt ec,simple