Va rog ajutor dau 15 puncte! Cei care se pricep la matematica!

a) x/y=z/t=u/v=2/3
(x+z+u)/(y+t+v)=2/3
(x+z+u)/12=2/3
x+z+u=(12×2)/3
x+z+u=8
b) x/y=z/t=u/v=2/3
(x+z+u)/(y+t+v)=2/3
(x+z+u)/15=2/3
x+z+u=(15×2)/3
x+z+u=10
c) x/y=z/t=u/v=2/3
(x+z+u)/(y+t+v)=2/3
(x+z+u)/21=2/3
x+z+u=(21×2)/3
x+z+u=14