a)7/9-x/3=1/9
x/3=7/9-1/9
x/3=6/9(simplificam fractia 6/9 cu 3,adica impartim la 3)
x/3=2/3
x=2
b)2/x-2/15=8/15
2/x=2/15+8/15
2/x=10/15(simplificam fractia 10/15 cu 5,adica impartim la 5)
2/x=2/3
x=3
c)9/14-2/x=5/14
2/x=9/14-5/14
2/x=4/14(simplificam fractia 4/14 cu 2,adica impartim la 2)
2/x=2/7
x=7
d)x/21-1/3=3/21
x/21=3/21+1/3(amplificam fractia 1/3 cu 7,adica inmultim cu 7)
x/21=3/21+7/21
x/21=10/21
x=10
