The following functions are known: 1. Y = 2x-1; 2. Y = - x; 3. Y = 4x; 4. Y = 2 / x, where are the positive proportion functions?

The following functions are known: 1. Y = 2x-1; 2. Y = - x; 3. Y = 4x; 4. Y = 2 / x, where are the positive proportion functions?

2,3,4