I need help please ??

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?

Someone answer this asap for gabriella uses the current exchange rate to write the function, h(x), where x is the number of u. s. dollars and h(x) is the number of euros, the european union currency. she checks the rate and finds that h(100) = 7.5. which statement best describes what h(100) = 75 signifies? a. gabriella averages 7.5 u. s. dollars for every 100 euros. b. gabriella averages 100 u. s. dollars for every 25 euros. c. gabriella can exchange 75 u. s. dollars for 100 euros. d. gabriella can exchange 100 u. s. dollars for 75 euros.

More challenges: 1) factor out the indicated quantity.8mn² + 7mn - m : factor out the quantity -m2) factor the polynomial by grouping.2vw + 7cv + 14cw + 49c²3) factor completely using the difference of squares along with factoring by grouping.25v³ - 25v² - 4v + 44) factor the sum of cubes. 125x³ + 645) q³ + 27r³6) factor completely. use difference of squares.729p^6 - 6^67) solve the equation(7x + 4)(9x - 1) = 08) a. find the values of x for which f (x) = 0b. find f (0)f (x) = x² + 2x - 489) find the x and y-intercepts for the function defined by y = f (x)f (x) = (x + 3)(x + 4)(x - 1)²10) factor the trinomial completely by using any method. remember to look for a common factor first. 3v² - 2v - 16