The following functions are: 1. Y = - 3x + 4 2. Y = 7 / 5x 3. Y = 1 + 2 / x 4. Y = x & # 178; + 25. Y = X-1 / 2, where is a linear function?

The following functions are: 1. Y = - 3x + 4 2. Y = 7 / 5x 3. Y = 1 + 2 / x 4. Y = x & # 178; + 25. Y = X-1 / 2, where is a linear function?

① (2) and (5) are linear functions