Evaluate the expression for the given values 5x + 3y when x=3 and y = 5

Mr switzer needs to buy new 1-foot tiles to cover his bathroom floor. the floor is 12 feet long and 8 feet wide. each square foot of tile will cost $1.79. in dollars what will be the total cost of the tiles he needs to buy.

Jim had 15 minutes to do 5 laps around his school what would his time be

Anyone know these questions? i need ,.