Say i love cheese for sum points

And employee salary increased by $4500 which represents a 15% raise what is the rate of the increase

Use the four functions below for this question. compare and contrast these four functions using complete sentences focus on the slope and y- intercept first, and then on any additional properties of each function

[10 points, algebra 2]according to my answer key the restrictions are -1 and 4. but why not positive 1?