The right answer for the question that is being asked and shown above is that: In the function f(x) = 4(x2 − 6x + ____) + 20, what number belongs in the blank to complete the square?
x2 - 6x + 9
So the answer on the blank space is 9. It should be a perfect square.
= 6/2
= 3^2
= 9