How to solve this?

Question

An object is launched from a platform. It’s height (in meters), x seconds after the launch, is modeled

h(x)=-5(x-4)²+180

how many seconds after being launched will the object hit the ground?

Answer 1

0 = 5(x - 4)² + 180

Can you solve for x and answer?

Answer 2

0 = -5(x-4)^2 + 180

-180 = -5(x-4)^2

36 = (x-4)^2

+-6 = x-4

x = 4+6=10 or x = 4-6=-2

x is time and cannot be negative

so 10 seconds