Hi HELP ME PLS WITH THESE FIVE QUESTIONS

BTW on the first question, I did not mean to put Subtract 4 from 20
ALSO BRAINLIEST FOR WHOEVER ANSWERS THESE QUESTIONS CORRECTLY!

I'm being volume of cylinder with 13 in. radius and 30 in height answer choices in pic

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

Rewrite the following quadratic functions in intercept or factored form. show your work. f(x) = 3x^2 - 12