How do you evaluate the limit x-2 as x approaches 1?

Plug in the value $1$ into $x$.
${\lim}_{x \to 1} x - 2 = 1 - 2 = - 1$
It only starts to get complex when you plug in the value that $x$ approaches, and you're left with an indeterminate form.
(ie. $\frac{0}{0}$ or $\frac{\infty}{\infty}$ or ${\infty}^{\infty}$) . . . the list goes on.