Answer:
Answer in explanation
Explanation:
The graph of f does not cross the x-axis. We know this because for any value x, we always get that x^2+4 is positive. x^2 is positive or zero ( 0 or greater than 0) for any x but adding 4 to it makes It 4 or greater than 4.
The discriminant is negative.
That is, b^2-4ac is negative.
Upon comparing ax^2+bx+c to x^2+4 we see that a=1, b=0, and c=4..
Plugging those into b^2-4ac gives
(0)^2-4(1)(4)
=0-16
=-16.
Negative discriminant implies two nonreal zeros so it will not cross the x-axis.
(Positive discriminant implies 2 real and zero discriminant imples 1 real.)