1. The problem statement, all variables and given/known data Driving along a steady speed of 26m/s and suddenly see a child 150m from you. Breaks can produce acceleration of -2.5m/s² but it takes time to get the foot from the gas to the brake pedal. How much time do you have, if to avoid hitting the child? Known: d=150m a=-2.5m/s² Vi=26m/s t=? 2. Relevant equations d=Vit+½at² 3. The attempt at a solution 150=26(t)+½(-2.5)t² 150=26t+(-1.25)t² 150=26t-1.25t² 1.25t²-26t+150=0 Quadratic formula: x=[26±√(-26)²-4(1.25)(150)]/2(1.25) x=[26±√676-750]/2.5 x=[26±√-74]/2.5 x=[26±8.6i]/2.5 Here I got stuck. How can I solve it if I have an imagery number? I guess my way is wrong?