Is the relation a function (-5,,-,7)

How do i do this activity, is appreciated

An investment decreases in value by 30% in the first year and decreases by 40% in the second year. what is the percent decrease in percentage in the investment after two years

Acampus club held a bake sale as a fund raiser, selling coffee, muffins, and bacon and eggs sandwiches. the club members charged $1 for a cup of coffee, 3$ for a muffin , and $4 for a back. and egg sandwich. they sold a total of 55 items , easing $119. of the club members sold 5 more muffins than cups of coffee, how many bacon and egg sandwiches he’s did they sell