Robert bought one 4.5-lb bag of dog food for $3.89, a 7.5-lb bag of cat food for $6.69, and two 2.3-lb bags of birdseed for $1.89 each. how much did he pay for the animal food?

The party planning committee has to determine the number of tables needed for an upcoming event. if a square table can fit 8 people and a round table can fit 6 people, the equation 150 = 8x + 6y represents the number of each type of table needed for 150 people.