You’re gonna have to use the quadratic formula here and a bit of thinking. We know y is height, and once it touches the ground, it will be 0.
(-b +- sqrt b^2 - 4ac)/2a
2 +- sqrt(4 + 48(400))/-32
(2 +- 138.58)/-32
We don’t want a negative time because it’ll make no sense. So do subtraction
(2-138.58)/-32 = 4.27 seconds aka 4.3 seconds
