Select all the correct answers(ASAP)

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

Pick the expression that matches this description: a polynomial of the 5th degree with a leading coefficient of 7 and a constant term of 6 (choice a) 7x^5+2x^2+6 (choice b) 7x^6−6x^4+5 (choice c) 6x^7−x^5+5 (choice d) 6x^5+x^4+7

Which inequality statement describes the two numbers on a number line? "? 7 and a number 5 units to the right of ? 7"