i found part a, which was -10, but i don't understand how you can use this to state the number of x-intercepts (the answer in the book says there's one intercept). any help would be appreciated :)
i found part a and my answer was a deceleration of 0.6944...m/s, which was correct. i tried solving part b, but i kept getting an answer different from the textbook (the textbook answer is 250m)