3 x^2 +30 x +75 factored completely

Imade a fort for my pet gorilla by connecting two boxes. the first box is 555 meters long, 999 meters wide, and 999 meters high. the second box is 333 meters long, 888 meters wide, and 222 meters high. how many cubic meters of space does my gorilla have to play in her fort?

Asalesperson earns $320 per week plus 8% of her weekly sales. the expression representing her earnings is 320 + 0.08x. which of the following describes the sales necessary for the salesperson to earn at least $1000 in the one week?

How is this equation completed? i cannot find any examples in the book.