Number 3 i would say i think it is
Step-by-step explanation:

Answer:
a=1/2
Step-by-step explanation:
Step 1 distribute the 5 across (8+0.2)
6^3+5(8+0.2)
6^3+40+1
6^3+41 (<em>I simplified the +40 and the +1</em>)
Step 2 take 6 to the power of 3
6^3+41
6x6x6 6x6=36 36x6=216
216+41 (<em>Simplify!</em>)
257
I hope this helped!