From a point at a height of 100 m above the surface of the Earth, a body is thrown vertically downward at a speed of 10 m / s

From a point at a height of 100 m above the surface of the Earth, a body is thrown vertically downward at a speed of 10 m / s. How long will it take to reach the Earth’s surface?

we succeed
h = V0 * t + g * t² / 2
2 * h = 2 * V0 * t + g * t²
g * t² + 2 * V0 * t-2 * h = 0
10 * t² + 20 * t-200 = 0
t² + 2 * t-20 = 0
t (1,2) = – 2 + -√84 / 2
t = 3.6
Answer: 3.6