What kind of equation is 4x+3y=7

Find the average rate of change for f(x) = x2 − 3x − 10 from x = −5 to x = 10.

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

Pls yall i really need the answer fr fr