PLEASE EXPLAIN. I NEED HELP GIVING POINTS !! :))

B' is at 0,0

Step-by-step explanation:

You can determine the translation T (?, ?) by counting how far A is moved to A'.  Going from A to A', you move -4 points on the x axis and +1 on the y axis.

So the translation or T is     T ( -4, 1 ).  Each point will now follow that same translation.  Moving B 4 points to the left and 1 point upward, puts B' at 0,0.