Răspuns:
3.
x=2y/3
a)(3•2y/3) : 4y =
2y : 4y =
1/2
b)(2y/3 + 2) : (y+3) =
((2y+6)/3 • 1/(y+3) =
2(y+3)/3 • 1/(y+3) =
2/3
4.
5a=2b (produsul mezilor = produsul extremilor)
a)a/b=2/5
b)a=2b/5
(2b/5 + 2) : (b+5) =
(2b+10)/5 • 1/(b+5) =
2(b+5)/5 • 1/(b+5) =
2/5