during a five day fundraiser, shantell sold 8 boxes of greeting cards the first day, 6 boxes the second day, 10 boxes the third day, and 7 boxes the fourth day. if she sold a total of 45 boxes of greeting cards during the five days, write an equation that can be used to find the number of boxes shantell sold the fifth day. explain two methods of solving this equation. then solve the equation.