The given expression is
[tex]x^2+1[/tex]We can not factorize this expression bt the normal factorizing ways
Because it is a binomial with + as a middle sign can not be distributed into 2 factors
Then there is no factorizing for the given binomial
If the sign between the two terms is (-), then we can factorize it into two same factors with different middle sign
We can use the complex numbers to factorize it
[tex]\begin{gathered} x^2=(x)(x) \\ 1=(i)(-i) \\ (x)(i)+(x)(-i)=(xi)-(xi)=0 \\ (x+i)(x-i) \end{gathered}[/tex]Then the factors are (x + i) and (x - i)
[tex]x^2+1=(x+i)(x-i)[/tex]