Show that x^2 - 8x +17 <0 for all real values of x
consider the discriminant b2-4ac 82-4x1x17 64-68=-4 discriminant is below 0, there are no real roots therefore x2 - 8x +17 <0
consider the discriminant b2-4ac 82-4x1x17 64-68=-4 discriminant is below 0, there are no real roots therefore x2 - 8x +17 <0