Please explain your answer will give brainliest

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?

Find two numbers if their sum is 91 and the ratio is 6: 7?

Select all of the following expressions that are equal to 2.5.