who can answer the rest

Answer:
[tex]\large \boxed{\sf \ \ \ (7x^2+4)(x^2+2) \ \ \ }[/tex]
Step-by-step explanation:
Hello,
[tex]7x^4+18x^2+8\\\\=7x^4+4x^2+14x^2+8\\\\=x^2(7x^2+4)+2(7x^2+4)\\\\=(7x^2+4)(x^2+2)[/tex]
Hope this helps.
Do not hesitate if you need further explanation.
Thank you