9) (3 marks) Certain superstores will often price match or even beat a competit price by 10%. The function g (x) =0.90x represents the sale price of a piece merchandise at such a superstore. The function f(x) =0.13xrepresents the owed on a purchase with a selling price of x dollars. a. Write a function that represents the HST owed on an item with a pri of x dollars after it has been beaten by 10%. b. How much HST would be charged on a $39.99 purchase if this price also lowered by 10% first? 10) (5 marks) A frustrated office worker throws his laptop out of his business's rise office building. The height, h, in meters of the laptop above the ground seconds can be modelled by h(t) =125 - 5t-. a. Determine the average rate of change between the third and fourth s of the laptop's flight. b. Estimate the rate at which the laptop hits the ground