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What are the domain and range of the function? f(x) = -4 (sqrt)x

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?

A10 inch cookie cake is divided into 8 slices. what is the area of 3 slices