Please answer correctly

Select all the correct answers. what is 221,000,000,000,000,000,000 expressed in scientific notation?

Prove that the sum of two consecutive exponents of the number 5 is divisible by 30.if two consecutive exponents are 5n and 5n + 1, then their sum can be written as 30.

Consider the expression below. 9 + 4(x + 2) – 3.1 select the term that best describes "3" in the given expression. o a. coefficient variable exponent constant