A contractor is constructing the house shown in the figure. The cross section up to the roof is in the shape of a rectangle.
The area of the rectangular floor of the house is 2500 square
feet. Express the perimeter of the rectangular floor, P, as a
function of the width of the rectangle, 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?