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)}

The linear combination method is applied to a system of equations as shown. 4(.25x + .5y = 3.75) → x + 2y = 15 (4x – 8y = 12) → x – 2y = 3 2x = 18 what is the solution of the system of equations? (1,2) (3,9) (5,5) (9,3)

What is the ratio of the length of an object in yards to the length of the same object in miles?

Evaluate the discriminant of each equation. tell how many solutions each equation has and whether the solutions are real or imaginary. x^2 + 4x + 5 = 0