lim √x²-4x+2 - (x+4) ... x → 0

=( (√x²-4x+2) - (x+4) . ( (√x²-4x+2) + (x+4)
----------------------------------------------------------
( (√ x²-4x+2) + (x+4)

= x² - 4x +2 - (x² + 8x +16)
------------------------------------
( √x²-4x+2 ) + (x+4)

= -12x - 14
-------------------------------
(√x² - 4x + 2) + ( x+4)

= -12.0 - 14
--------------------------------
( √ 0² - 4 . 0 +2) + 0 +4

= -14 / 4 + √2