The expression
[tex]16p^4+4p^3[/tex]Has coefficients:
[tex]16\text{ and 4}[/tex]16 has factors 1, 2, 4, 8 and 16. Meanwhile 4 has factors 1, 2 and 4. Therefore the GCF of this two numbers is 4.
Now, the variable has GCF of p^3. Therefore, the expression in factored form is:
[tex]4p^3(4p+1)[/tex]