Răspuns:
Explicație pas cu pas:
3.
a)5/12+5/24=(10+5)24=15/24=5/8
b)26/21+13/14=(26×3+13×3)/42=(72+39)/42=117/42=39/13
c)4/15+3/20=(2×4+3×3)/30=(8+9)/30=17/30
d)5/24+1/12+3/8=(5+2+12)/24=19/24
e)7/30-3/20=(7×2-3×3)/60=(14-9)/60=5/60=1/12
f)8/15-9/20=(8×2-9×3)/30=(16-27)/30=-9/30=-3/10
g)8/21-4/35=(8×5-4×3)/105=(40-12)/105=28/105=4/15
