A function is given by a table of values, a graph, a formula, or a verbal description. Determine whether it is one-to-one.
$f$ is not one-to-one because $2 \neq 6,$ but $f(2)=2.0=f(6)$
The question here is whether or not F is a 1 to 1 function. So in order to be 1 to 1 for every X value, there's only one why value? And for every y value, there's only one X value. So when we look at the table, we see that we have a Y value of 2.0, that corresponds to two different X values, so that means it's not 1 to 1.