It cost $2.80 to make a sandwich at a local deli shop to make a profit the deli sells it at 170% of the cost how much should i sell the sandwich board

[10 points, algebra 2]according to my answer key the restrictions are -1 and 4. but why not positive 1?

Math it's appreciated. (picture provided)

Louis wants to carpet the rectangular floor of his basement the basement has an area of 864 square feet the width of the basement is 2/3 its length what is the length of lewis's basement