Which of the sets of ordered pairs represents a function?

a = {(2, −2), (5, −5), (−2, 2), (−5, 5)}
b = {(4, 2), (4, −2), (9, 3), (9, −3)}

Write an algebraic expression to match each statement a. four less than 8 times a number b. twice the difference of a number and six c. nine from a number squared

Given the system of equations presented here: 2x + 4y = 14 4x + y = 20 which of the following actions creates an equivalent system such that, when combined with the other equation, one of the variables is eliminated? multiply the second equation by â’4 to get â’16x â’ 4y = â’80 multiply the second equation by â’1 to get â’4x â’ y = â’20 multiply the first equation by 2 to get 4x + 8y = 28 multiply the first equation by â’1 to get â’2x â’ 4y = â’14

What is the following product? sqrt 30 • sqrt 10