While a problem, this is more for me to learn to help my kid with her own homework. I used to be great at this sort of thing but for some reason I just can't get my head around this one. -125 = 39.1t - 4.9t^2 I need to find the value for t. It should be approx 10.4. I would just like to see the steps to get there. I know that I should re-write this as : 4.9t^2 - 39.1t - 125 = 0 But after this I am stuck... Thx!