The above expression is not in its simplest form, and we need to simplify it, that is what asked in the question.
Given equation,

First of all, let's open the parentheses to combine the like terms for simplifying.

Arranging the like terms, x² with x², x with x and constant terms near to each other.

Simplying further,


So, the correct option is C
<u>━━━━━━━━━━━━━━━━━━━━</u>
So that equation was definitely correct...
When you expand the equation in the bracket you'll find out that you'll get a^6 + 4a^4 + !6a^2 - 4a^4 - 16a^2 -64. then your final result will be a^6 - 64
<span />
Angle 8 because supplementary is two angles whose sum is 180°.