2/5 over 2/3, I don't understand

Omar is going on a road trip! the car rental company offers him two types of cars. each car has a fixed price, but he also needs to consider the cost of fuel. the first car costs $90 to rent, and because of its fuel consumption rate, there's an additional cost of s0.50 per kilometer driven.

The surface area of the triangular prism is .

What is the axis of symmetry of the function f(x)=-(x+ 9)(x-21)