Sarai has decided to take a risk. She's been saving money and now she's ready to invest in stocks. Most of her stocks give her a great return, but one–Bambi's Beach Bonnets–is a mixed story. The value of her shares in Bambi's Beach Bonnets over timem is modeled by the function v(t) = −2x 2 + 22x + 280, where v represents the value of her investment and t represents time in weeks. (a) What key feature of the function tells us when her investment was worth the most?