20. The temperature of a city during a week was 1° C, -6°C, 14°C, -9°C, -15°C, 8°C and -7°C. What was the average daily temperature of the town
for the week?

The average temperature would be -2°Celsius

You just add up all the numbers, and the average of the numbers is the sum of all the numbers divided by the amount of numbers.

1+-6+14+-9+-15+8+-7=-14

-14/7=-2

yes because there is exactly one y value for every x value

for function there can't be more than one value for every x value