Răspuns:
rezolvarea e mai sus...sper ca te-am ajutat=)
3.a)4/15+2/3=4/15+10/15=14/15
b)15/11+13/22=30+13/22=43/22
e)1/4+3/16=4+3/16=7/16
f)5/6+6/18=15+7/18=22/18
4.a)3/4+5/3=9+20/12=29/12
b)15/7+13/11=165+91/77= 256/77
e)11/5+3/7=77+15/35=92/35
f)1/11+5/19=19+55/209=74/209
