Answer:
(2x - 1)^2
Step-by-step explanation:
We can reverse engineer the solution...
to complete the square, we know (2x + __)^2 will generate the 1st term 4x^2
To generate the 2nd term, we will need -1, so (2x - 1)^2....
When expanded, we will have 4x^2 - 4x + 1, which we completed the square.