Answer:
t = 1/8 ± √(1 − 4d) / 8
Step-by-step explanation:
d = -16t² + 4t
Move everything to the left side:
16t² − 4t + d = 0
Solve with quadratic formula:
t = [ -(-4) ± √((-4)² − 4(16)(d)) ] / 2(16)
t = [ 4 ± √(16 − 64d) ] / 32
t = [ 4 ± 4√(1 − 4d) ] / 32
t = [ 1 ± √(1 − 4d) ] / 8
t = 1/8 ± √(1 − 4d) / 8
