What is the square root of negative 1 divided by 8

Select a graph that have an equation with a < 0

Arestaurant offers delivery for their pizzas. the total cost the customer pays is the price of the pizzas, plus a delivery fee. one customer pays $23 to have 2 pizzas delivered. another customer pays $59 for 6 pizzas. how many pizzas are delivered to a customer who pays $86?

Im so bad at fractions they are not my best math thing to work on