What is the distance between 12 7 and 3 7 !

How do you use the elimination method for this question? explain, because i really want to understand!

The width of a rectangle is 20 units. can the perimeter p of the rectangle be 64 units when its length x is 11 units? no, because p = 2x + 2(20) no, because p ≠ 2x + 2(20) yes, because p ≠ 2x + 2(20) yes, because p = 2x + 2(20)

Hi, can anyone show me how to do this problem? 100 points for this. in advance