With these questions, I always think how to write out the expression in terms that are more simple to understand:
I would write out the expression as '(x-8)(x-8)' which really shows what the power of 2 is representing.Then we expand the brackets: each component must be times by one other.
The 'x' in the first bracket multiplies the 'x 'in the second bracket: x2The 'x' in the first bracket multiplies the '-8' in the second bracket: x2- 8x
The '-8' in the first bracket multiplies with the 'x' in the second bracket: x2 - 8x -8xThe '-8' in the first bracket multiplies with the '-8' in the second bracket (remember when a '-' and a '-' number multitiply one another, they become the postive product) : x2 -8x -8x + 64
Then simplify; x2 -16x +64