Where is science on the pick a subject that is where me real answer is at

In a graph with several intervals o data how does a constant interval appear? what type of scenario produces a constant interval?

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?

If your teacher tells you to do questions 6 through 19 in your math book for homework, how many questions is that