Hey can someone who is very nice and very smart help me with this? I am failing Math so I really need to pass this!

At the beginning of the day, stock xyz opened at $6.12. at the end of the day, it closed at $6.88. what is the rate of change of stock xyz? a. 1.17% b. 11.0% c. 12.4% d. 81.5%

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

Determine the difference: 3.2 × 1010 – 1.1 × 1010. write your answer in scientific notation.