Answer
False
Work Step by Step
you can see this by subbing it into an equation. lets suppose that f(x) = $x^{2}$
and our value for are variable are s = 2 and t = -2. when we sub this in we get
f(2) = 4
f(-2) = 4
however
-2 $\ne$ 2
this shows how the y values can be the same with different x values