Write the expression below as a power then evaluate it when y=4

y x y x y x y x y

Ihave trouble finding the nth term of a linear sequence

Sanya noticed that the temperature was falling at a steady rate of 1.4 degrees every hour from the time that she first checked her outdoor thermometer. by 6 a.m., the temperature had fallen 21 degrees. which expression can you use to find how many hours earlier she had first checked the thermometer?

Which coefficient matrix represents a system of linear equations that has a unique solution ? options in photo*