The range of a relation is given. −2, −1, 0, 1, 2-2, -1, 0, 1, 2 Which domain would make the relation not a function?

Question

A	12, 1, 0, −1, −1212, 1, 0, -1, -12
B	0, 1, 2, 3, 40, 1, 2, 3, 4
C	−2, −1, 0, 1, 2-2, -1, 0, 1, 2
D	0, −1, 2, 1, 0

Answer 1

y=x where x ∊ {-2 -1 0 1 2 } fits the range. But so does y²=x² or y²-x²=0. This is a relation, not a function.

When x=-2, y=±2. This is not a function because x=2 also gives y=±2. This function has the same range as y=x. Graphically it resembles a cross formed by the lines y=x and y=-x. Apart from x=0, each value of x in the domain produces two values for y.