Jack is at the library, and his school is 20 blocks south of the library. The park is 20 blocks north of the library. When Jack is at the library is he closer to the park or his school? How could the number zero be used in the situation? Explain

it would be 6xy and -16xy.

what are the

sample answer: you can determine whether each element of the domain is paired with exactly one element of the range. for example, if given a graph, you could use the vertical line test; if a vertical line intersects the graph more than once, then the relation that the graph represents is not a function.