Infamous cat burglar Dogperson (that name is just as legitimate as Catwoman) leaps from a penthouse window. At first, their fall is modeled by F（t）ニーt^2-t+300 where tis the time since theyjiumped. Afera certain amount of time, they open their parachute, after which, their fall is modeled by P(t) = -t + 284. At how many seconds did Dogperson open their chutes?