The quadratic function d=−5x2+77 models a sled's distance, in feet, from the bottom of a hill x seconds after the sled starts moving down the hill. When does the sled get to the bottom of the hill?

after 3.92 seconds

Step-by-step explanation:

Given the quadratic equation that models the sledge distance expressed as;

d = -5x^2 + 77

The sled get to the bottom of the hill at when d  = 0. Substitute into the equation given;

0 = -5x^2 + 77

5x^2 = 77

x^2 = 77/5

x^2 = 15.4

x = √15.4

x = 3.92

Hence the sled get to the bottom of the hill after 3.92 seconds