Help me please it’s 10 points

What is the equation of the graph below? y=sec(x)-4

Answer asap and if you do you will get brainliest. catherine buys a gallon of ice cream from the store. after taking it home, she eats a fifth of a gallon of ice cream. her sister eats some of the ice cream as well. if two-thirds of the original amount of ice cream is left, then what fraction of a gallon of ice cream did her sister eat?

What is the solution for 6 - 7/8? explain the steps.