How do you work this out ? h= -16t²+64+0=0

Add 64 and 0
then add 16t^2 from =0
then you should have h= 16t^2=64
then take the square root of both 16t^2 and 64
then you should have 4t +- 8
that should give you your answer

H = -16t² + 64 + 0
-16t² + 64 + 0
t = -64 +/- √(64² - 4(-16)(0))
                   2(-16)
t = -64 +/- √(4096 + 0)
                 -32
t = -64 +/- √4096
            -32
t = -64 +/- 64
           -32
t = -64 + 64        t = -64 - 64
         -32                     -32
t = 0                    t = -128
     32                         -32
t = 0                    t = 4

h = -16t² + 64t + 0                    h = -16t² + 64t + 0
h = -16(0)² + 64(0) + 0               h = -16(4)² + 64(4) + 0
h = 16(0) + 0 + 0                       h = -16(16) + 256 + 0
h = 0 + 0 + 0                             h = -256 + 256 + 0
h = 0 + 0                                   h = 0 + 0
h = 0                                         h = 0
(t, h) = (0, 0)                              (t, h) = (4, 0)

Magic man is here, but unfortunately he is broke won’t you him out

Ithink the answer is b.