Please help me I am stuck on number 4 and 5

The green family is a family of six people. they have used 4,885.78 gallons of water so far this month. they cannot exceed 9,750.05 gallons per month during drought season. write an inequality to show how much water just one member of the family can use for the remainder of the month, assuming each family member uses the same amount of water every month.

For the equations below which statement is true ?

Which property was used to simplify the expression? 3c+9 +4c=3c+4c+9