What property is 15+0=15

A. 90 degrees b. 45 degrees c. 30 degrees d. 120 degrees

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?

Factor the expression using the gcf. the expression 21m−49n factored using the gcf