How to write -540 from -40

How many square feet of out door carpet will we need for this hole? 8ft 3ft 12ft 4ft

What is the rate of change of a line that passes through (2,-5) and (6,-2)?

Astuntman jumping off a 20-m-high building is modeled by the equation h=20-5t^2, where t is the same in seconds. a high-speed camera is ready to film him between 15m and 10m above the ground. for which interval of time should the camera film him?