Domain of a Function
Algebra
For what values of $x\in \mathbb{R}$ is $$f(x) = \sqrt{x^2 - 3x + 2}$$defined as a real number?
A$(-\infty,1]\cup [2,\infty)$
B$(-\infty,1)\cup (2,\infty)$
C$[1,2]$
D$(1,2)$