Respuesta :

naǫ
[tex]x^2-2x+4=0 \\ \\ a=1 \\ b=-2 \\ c=4 \\ \\ \hbox{the discriminant: } \Delta=b^2-4ac=(-2)^2 - 4 \times1 \times 4=4-16=-12[/tex]

The answer is D.
[tex]ax^2+bx+c=0\\the\ discriminant:\Delta=b^2-4ac\\-------------------\\Your\ example:\\x^2-2x+4=0\to a=1;\ b=-2;\ c=4\\\\thereore\ \Delta=(-2)^2-4\cdot1\cdot4=4-16=\fbox{-12}\\\\Answer:\boxed{D.\ -12}[/tex]