To represent the number of squares after steps, Diego and Jada wrote different equations. Diego wrote the equation f(n)= (n+1) 2 . Jada wrote the equation f(n) = n 2+ 2n + 1. Are either Diego or Jada correct? Explain your reasoning.

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?