Please help me hurry a lot of points

In the past, professional baseball was played at the astrodome in houston, texas. the astrodome has a maximum height of 63.4 m. the height of a baseball t seconds after it is hit straight up in the air with a velocity of 45 ft/s is given by h = -9.8t2 + 45t + 1. will a baseball hit straight up with this velocity hit the roof of the astrodome? use the discriminant to explain your answer.

Which expressions are equivalent to k/2 choose 2 answers: a k-2 b 2/k c 1/2k d k/2 e k+k

(x-5)1/2+5=2 what is a possible solution?