#### Answer

not one-to-one

#### Work Step by Step

A function $f$ is a one-to-one function if different values of the domain correspond to different values of the range.
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When we see $($... x ...$)^{2}$ in the function expression,
our first thought should be
"this is probably not one-to-one",
because, for example, $1^{2}=(-1)^{2}$...
We can get 1 in the parentheses if x=0
and $-1$ if $x=-2. $
So, for two different values from the domain, $0$ and $-2$...
$f(0)=2(1)^{2}-6=-4$
$f(-2)=2(-1)^{2}-6=-4$
... we have the same function value.