sorry, forgot to show my steps so far:

for the first qu:

I have it up to: 1/(4x^4)(-27x^12)

I don't understand how they got a 4 over 27x^16? I would think it would be a 1 over 27x^16.

For the second question:

I have 5sqrt(3a^4) = 48

and then I'm sorta stuck... could it be: 5*4=20, so (a^20)/3 = 16?