Răspuns:
Explicație pas cu pas:
a) 14/5*(27/10*20/63-14/15*25/28)
14/5*(54/63-5/6)
14/5*(108/126-105/126)
14/5*3/126=3/45=1/15
b) [(7/15+5/15-3/15)*5/4+(2/4-1/4)*12/5]*2/7
(3/5*5/4+1/4*12/5)*2/7
(3/4+3/5)*2/7
(15/20+12/20)*2/7
27/20*2/7=27/70
