a) Since the powers are the same, we can add them together.
[tex]8n^3+5n^3=13n^3[/tex]
b)Using the laws of indices;
[tex]8n^3.5n^3=40n^{3+3}=40n^6[/tex]
c)
[tex]8n^3+8n^5[/tex]
The above is not with the same powers hence cannot be combine but we can factorise.
[tex]=8n^3(1+n^2)[/tex]
d) Using the laws of indices;
[tex]8n^3.8n^5=64n^{3+5}=64n^8[/tex]
