Respuesta :

Answer:

Undefined.

Step-by-step explanation:

m = y2-y1 / x2-x1

m = 3 - 2 / 1 - 1

m = 1/0, which is undefined.

You can also tell because (1,2) and (1,3) is a vertical line, which means the slope is undefined.

The answer would be x = 1