Answer:
Step-by-step explanation:
Hello, please consider the following.
[tex]x^4+xy^3+x^3+y^3\\\\=x^3*x+x*y^3+x^3+y^3\\\\=x(x^3+y^3)+x^3+y^3\\\\\boxed{=(x+1)(x^3+y^3)}\\[/tex]
Thank you
