Question

Which of the following relations is a function?
A.{(1, 2), (1, 0), (-3, -4)}
B.{(1, 2), (3, 2), (1, 4)}
C.{(1, 2), (3, 2), (5, 2)}
D.{(1, 2), (-3, 2), (-3, 3)}

Answer 1

What they mean when they say "function" is an "explicit function".

Explicit function - a function that passes a vertical line test. (very basically)

What it means that the function passes a vertical line test, is that if you
go ahead and draw a vertical line anywhere through the function, then
it must (to pass this test) not intersect with the function more than once.

OR, this test is satisfied if no coordinates have the same x-coordinate more than once.

Answer 2

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