The side length of the square f is x- 1,
The side length of the square e is x-2,
The side length of square c is x+ 12 or x-3;
(2) Let the side length of the largest square B in the drawing be x meters, and get it from the image.
QM=x- 1+x-2，PN=x+x+ 12
QM = PN，
∴x- 1+x-2=x+x+ 12，
∴x=7.
A: The value of X is 7;
(3) The rest of the project will be constructed by team B alone, and it will take y days to complete.
( 1 10+ 1 15)×2+ 1 15y = 1，
Solution: y = 10.
A: It will take 10 days to complete.
So the answer is: y- 1, y-2, Y+ 12.