Please help me asap!!

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

True or false look at the picture pls : /

Acompany that manufactures and sells guitars made changes in their product range. from the start they had 20 models. then they reduced the number of models to 15. as a result, the company enjoyed a 10% increase in turnover. - how much did the stock level change? in (%)