Change the Cartesian integral to an equivalent polar integral, and then evaluate. S LvS- (x² + y²) dx dy 625x 8 125x 8 125 4. 25 8

A student needs to answer 20 out of 30 questions on a test. Find the number of ways the student can choose if the student must answer the first 8 questions on the test.

Professor Tough's final examination has 17 true-false questions followed by 3 multiple-choice questions. In each of the multiple-choice questions, you must select the correct answer from a list of six. How many answer sheets are possible? answer sheets

I only need the answer for the one marked in yellow, what did I do wrong and what is the correct answer? Thank you.

Is a the only correct answer?