repede vă rog!dau coroană!!!!

Răspuns:
Explicație pas cu pas:
a·b=15/7 si b=10/21 ⇒a=a·b/b=15/7·21/10=9/2
a·b=3/8 si a·b·c=33/44=3/4 ⇒c=3/4:3/8=3/4·8/3=2
a·b=4/5 a·c=7/5 a=22/10=11/5 ⇒b=4/5:11/5=4/11
c=7/5:11/5=7/11
b+c=4/11+7/11=11/11=1