Question

Can someone plz check this? I'm not sure I got them right.

Answer 1

for a set of coordinate pairs, a function set, will not have a repeat on the x-coordinate, namely, the "x"s do not repeat, no x-repeats.

now, look at 4)
`\bf \begin{array}{ccll} x&y\\ \text{\textemdash\textemdash\textemdash}&\text{\textemdash\textemdash\textemdash}\\ -2&-4\\ 0&-2\\ 2&0\\ 4&2 \end{array}`

the x-values are -2, 0, 2, 4, no repeats, so it IS a function.

10)


`\bf \{(-1,3),(\stackrel{\stackrel{re peat}{\downarrow }}{1},4),(4,7),(\stackrel{\stackrel{re peat}{\downarrow }}{1},0)\}\impliedby \textit{not a function}`

the other ones, you can check for that, you're correct. For example for 6), the graph doesn't pass the "vertical line test", so is not a function.