What’s a function in math

A relation from a set of inputs to a set of possible outputs where each input is related to exactly one output

Step-by-step explanation:

See below.

Step-by-step explanation:

A function is a relation in which each input has only one output.

For example f(x) =  3x + 1  is a function. Whatever value of x you use the value of f(x) is only one value.

But the relation  y = √x is not a function because for example if x =  4 then x = 2 or -2   - two outputs for the same input.