Which set of ordered pairs is a function?

Mr. bernard needs to order more boxes for his 16 inch diameter “super pizza.” use 3.14 to approximate π.

There are 20 children in the cast of a class play and 8 of the children are boys of the boys 4 have a speaking part in the play and of the girls 8 do not have a speaking part in the play if a child from the cast of the place chosen at random what is the probability that the child has a speaking part

Which of the following expressions is equal to 2x^2+8