Let a=(1,5,−1)a=(1,5,−1), b=(−3,6,−5)b=(−3,6,−5), c=(0,4,−9)c=(0,4,−9), and d=(4,3,−5)d=(4,3,−5). find the area of the parallelogram determined by these four points, the area of the triangle abcabc, and the area of the triangle abdabd.

Anew shopping mall is gaining in popularity. every day since it opened, the number of shoppers is 5% more than the number of shoppers the day before. the total number of shoppers over the first 10 days is 1258 how many shoppers were on the first day?