Determine whether or not they are functions or not. please do all 6 if you can?

Aretha wanted to gather data about the cost of local bowling leagues in her area. she plotted the data and determined that the average bowling league costs consist of a one-time registration fee and a monthly fee modeled by the equation y = 15x + 20. identify and interpret the y-intercept in this model. the y-intercept is 20. this is the cost per month. the y-intercept is 20. this is the cost of registration. the y-intercept is 15. this is the cost of registration. the y-intercept is 15. this is the cost per month.

What number line represents the solution set for the inequality -1/2 greater than or equal to 4

‼️‼️‼️10 points‼️‼️‼️ me it’s important‼️‼️‼️‼️‼️