Question

a)Daca a+b=28 supra 15 si ac+bc=12 supra 25,determinati numarul c
b)Daca a-b=35 supra 108 si ac-bc=49 supra 72,determinati numarul c
DAU COROANAAAAAAA!!!!!!!!!!

Answer 1

1) ac+bc = c(a+b) = 12/25
Dar a+b = 28/15
Deci c*(28/15) = 12/25
c = (12/25):(28/15) = (12/25)*(15/28) = (3*3)/(5*7) =9/35 


2) a-b = 35/108
   ac-bc = c(a-b) = 49/72
Dar a-b = 35/108, atunci:
c*35/108 = 49/72
c = (49/72):(35/108) = (49/72) * (108/35) = 7*3/2*5 = 21/10