Question

Which relation does not represent a function?
A) a vertical line
B) y =
5
9
x - 3
C) a horizontal line
D) {(1, 7), (3,7), (5, 7), (7,7)}

Answer 1

If it passes a vertical line test its a function, not a horizontal line
{(1, 7), (3,7), (5, 7), (7,7)} < this is a function