2a) a+b=4si2/5; a=12/10=>a=6/5
a+b=22/5
6/5+b=22/5=>b=22/5-6/5
b=16/5
p: 6/5+16/5=22/5
22/5=22/5
b) a-b=1/9; b=1/2
a-1/2=1/9
a=1/9+1/2
a=2/18+9/18
a=11/18
c) a×b=1si5/6; a=2si4/9=>a=22/9
22/9×b=11/6
b=11/6:22/9=>b=11/6×9/22
b=3/4
Sper sa intelegi! Succes!
