Someone please solve this 3n+9n=-2(7-4n)-(1+n)

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?

[tex]5 \times1 \frac{12}{13} [/tex] me

Which strategy is used by public health to reduce the incidence of food poisoning?