You can just replace [tex]u[/tex] with 2:
[tex]2^2 - 4\times2 + 2 = 4 - 8 + 2 = \boxed{-2}[/tex]
Alternatively, you can complete the square.
[tex]u^2 - 4u + 2 = u^2 - 4u + 4 - 2 = (u-2)^2 - 2[/tex]
When [tex]u=2[/tex], the quadratic term vanishes and we again get -2.
