The path of a javelin thrown by Marita is given by the formula$\displaystyle h=-\frac{1}{16}(d-10)^2+9$where h meters is the height of the javelin above ground and d meters is the horizontal distance travelled.1. What are the possible values of d?

the book says the answer is 0=<d=<22,my question is what is the process of getting those values?