The point R has coordinates (-5,-5) and the image point R' has coordinates (2,-7).
If
- -5+a=2, then a=2-(-5)=2+5=7;
- -5+b=-7, then b=-7-(-5)=-7+5=-2.
Thus, the translation rule is
(x,y)→(x+7,y-2)
or 
If point U has coordinates (-5,1), then its image U' has coordinates (-5+7,1-2) that is (2,-1).
Answer: correct choice is B
Step-by-step explanation:
In set a, every element in the domain has only 1 image in the range. This is called a one-to-one correspondence.
However in set b, there is a many-to-one correspondence as more than 1 element in the domain has the same image.
rise over run
you can remember it doing the vertical over horizontal