Represent the following sentence as an algebraic expression, where "a number" is the letter x

Using d, e, and f as values on a triangle and d being 60 degrees, what is the value of e and f if d is 60 degrees? also, what do you notice about the values of e and f?

Create and solve a linear equation that represents the model, where squares and triangles are shown evenly balanced on a balance beam. assume the weight of a square is 1 unit and the weight of a triangle is unknown.

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?