Functions - Algebra I

Question

 Supposed G takes a student's grade and gives a student's name the same as the output. Explain why G is not a function.

Answer 1

Here, the students' grade is our x and the corresponding name is our y. You could have 2 or more grades that are identical (same x-value) but obviously with different names (y-value). This means that you would have 2 or more y-values (the names) at the same x-value (the grades). Accordingly, the "vertical line" test fails thus G not a function.