Question

Which relation is a function which is not !!??

Answer 1

B isn't

Answer 2

well C AND D are functions increasing by two, ithink it is either A OR B

Answer 3

A function can only have one "x-value" assigned for any y-value. As soon as you see two different y-values with the SAME x-value, it's not a function.

Like in graphic 1, B: you have x assigned "4" to all the y-values, so it's not a function.

Graphically, if you imagine a vertical line passing through the graph, to be a function, the line may only go through the graph ONCE

So
graphic 1: B
graphic 2: D

Answer 4

@pasta A function doesn't need to have a "specific" rule, as long as there is only one x-value associated to ANY y-value

Answer 5

An example wikipedia gives of an abstract function is here: http://en.wikipedia.org/wiki/File:Function_color_example_3.svg

Answer 6

thanks