Hey can somebody help me

For the function, f(x) = -5x 2, find f(-4).

Jada has a meal in a restaurant she adds up the prices listed on the menu for everything they ordered and gets a subtotal of $42.00. when the check comes, it says they also need to pay $3.99 in sales tax. what percentage of the subtotal is the sales tax

If value of cos330° is √3/2 then find tan165°.