What are the steps to find the lower and upper quartiles of a data set?

Don't know how to find x given these segment lengths

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?

Which of the following values are in the range of the function graphed below? check all that apply ! - will give the answer "brainliest! "