Question 978096
Y=x^2-5x+15.  The first doesn't factor.
 y=-×+10

Set them equal.
-x+10=x^2-5x+15
x^2-4x+5=0
x=(1/2)(4+/- sqrt (16-25)=2+/-(3i/2)

The two solutions are complex.  

{{{graph(300,300,-20,20,-5,50,-x+10,x^2-5x+15)}}}