During the video on the link (at 20 seconds) the narrator says that $(x^2+3)$ cannot be factored, however I believe that it can be factored to $(x-1)(x-3)$
https://www.youtube.com/watch?v=4IeZkmO0STg
There must be something missing in my understanding of this as I'm assuming the narrator is not incorrect,
If anyone could explain why this cannot be factored I would be very grateful.
-Connor
Roots are the values of X that makes entire LHS to be zero. In your case LHS is absent so if LHS is as you provided & if RHS is zero then $X^2 = -3$ So $X = \sqrt{-3}$ Meaning roots are imaginary or does not exists