When have I ever done this leave me alone please

Given f(x) = 17-x^2what is the average rate of change in f(x) over the interval [1, 5]?

Anyone know? will mark brainliest if you're correct!

For each polynomial, determine the degree and write the polynomial in descending order. a. –4x^2 – 12 + 11x^4 b. 2x^5 + 14 – 3x^4 + 7x + 3x^3