Question

fie y\x=1\3.Determinati valoarea expresiei x+y\x-y

Answer 1

x=3y
(3y+y)/(3y-y)=
4y/2y=
2

Answer 2

y/x = 1/3  ⇔  x/y = 3/1 
                          ↓
          $\frac{x+y}{x-y}=\frac{3+1}{3-1}=4/2=2$