2x²-24x+64=0 How do you solve my factoring this

Eric has challenged himself to walk 24,000 steps in 4 days. if eric walks the same number of steps each day, which function represents the number of steps eric still needs to walk to reach his goal with respect to the number of days since he started his challenge? a. y = 8,000x − 24,000 b. y = -8,000x + 24,000 c. y = 6,000x − 24,000 d. y = -6,000x + 24,000

Kari plans to sample 20 people of a population that contains 100 students. she wants to determine how many people wake up before 6 a.m. which sample is the most random?

I've tried but its still not right! what is ae ? enter your answer in the box. = units