If 10^x = 5, what is x?

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?

Ineed here’s a picture of the question

Si el duplo del mayor de dos numeros se divide entre el el triplo del menor, el cocient es 1 y el residuo 3, y si 8 veces el menor se divide por el mayor, el cociente es 5 y el residuo 1