Which transformation will always map a onto itself? a. a 90 degree rotation about its center. b. a reflection across one of its diagonals. c. a 180 degree rotation about its center. d. a reflection across a line joining the midpoints of opposite sides

Acoffee shop orders at most $3,500 worth of coffee and tea. the shop needs to make a profit of at least $1,900 on the order. the possible combinations of coffee and tea for this order are given by this system of inequalities, where c = pounds of coffee and t = pounds of tea: 6c + 13t ≤ 3,500 3.50c + 4t ≥ 1,900 which graph's shaded region represents the possible combinations of coffee and tea for this order?