pls help me im confused.. dont answer this just for points answer bc it will halp somebody benifit from it

Lin is writing an equation to model the proportional relationship between y, the total cost in dollars of downloading videos from a website, and x, the number of videos downloaded. she knows that the total cost to download 3 videos was $12. her work to find the equation is shown below. joylin’s work step 1 k= 3/12= 0.25 step 2 y= 0.25x where did joylin make her first error?

Can you me find the slope! (30 points)

Given the following linear function sketch the graph of the function and find the domain and range. ƒ(x) = -5x + 4