The second option because one same input cannot have two different outputs For example, x + 2 = y If I put in 3, y has to equal 5, nothing else. This makes the second option the only option that is a function Hope this helps!
In a function an input has a distinct output, so if I put 3 into a function and got 8, that is my answer and nothing else, if I put 3 again and get -2 then it isn't a function because I got a different answer. In the 1st, 3rd and 4th one there are two outputs for the same input so they aren't functions.
Step-by-step explanation: if you go on a certain site and you put in the equation, you press enter then it will pop up with what you want to do. Press graph, then you can compare the graphs and if it is the same you know it is correct
