Can someone please walk me through this?
It is comparing functions

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?

If you are trying to move an attached term across the equal sign (=), what operation would you use to move it?

The cost of using a service is $0.25 per min. what equation correctly represents the total cost c, in dollars, for d days of use?