Question

The following a function (6,3), (-1,2), (-1,-1), (4,3)

Answer 1

for an expression or relation to be a function, it must not have any x-coordinate values repeated, let's check this one

$\bf (6,3), (\stackrel{\stackrel{rep eated}{\downarrow }}{-1},2), (\stackrel{\stackrel{rep eated}{\downarrow }}{-1},-1), (4,3)\qquad \textit{not a function}$