it is not 1-1 nor onto..

not 1-1:

by def:

take f(x) = 9, then x = 1 or x = -1.

therefore not 1-1.

not onto:

for every element in the range, there must be an element in domain..

take -1 in range, does there an element in the domain that will give you -1 when mapped using your function?