How can i use models to add fractions?

What is f(3) for the quadratic functionf(x)=2x2 + x – 12? f -3g 3h 6i. 9

Answer asap ! the shortest path from point a to point b goes through a pond. to avoid the pond, you must walk straight 34 meters along one edge of the pond, then take a 90 degree turn, and again walk straight 41 meters along another edge of the pond to reach point b. about how many meters would be saved if it were possible to walk through the pond? a. 11 m b. 20 m c. 30.45 m d. 21.73 m

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?