Can some one me with this will give brainliest and explain how you got the answer

Write a polynomial that fits the description: a third-degree polynomial with leading coefficient -4

What is the standard deviation of the following data set rounded to the nearest tenth? 3, 17, 18, 15, 12, 21, 9

Cot(90° − x) = 1 the value of x that satisfies this equation is °. a. 60 b. 135 c. 225 d. 315