Answer:
What is missing is -5x - 20
Step-by-step explanation:
To find this, simply solve for the parenthesis as if it were a variable of its own. This will allow you to see exactly what is missing.
8x - (x - 20) = 2x - (_______)
8x - x + 20 = 2x - (_______)
7x + 20 = 2x - (_______)
5x + 20 = - (_______)
-5x - 20 = (_______)
So the answer for the parenthesis is -5x - 20