Answer:
The missing value of 64 or 8². The complete expression is x²- 64 or x²- 8².
Step-by-step explanation:
It is given that the difference of squares has a factor of x + 8.
The given expression is
x²- _____
Let the missing term in the given expression be a².
Using the algebraic formula, we get

It is given that one factor of the given expression is (x+8).


It means the value of a is 8 and the missing value of 64 or 8².
Therefore the complete expression is x²- 64 or x²- 8².