Well the definition of observer is a person who watches or notices something the definition of observation is the action or process of observing something or someone carefully or in order to gain information or a remark, statement, or comment based on something one has seen, heard, or noticed so from my conclusion the answer is their eyes
The solution is where the 2 graphs intersect At A and B. x + y + 2 = 0 transforms to y = -x - 2 which has slope -1 and y-intercept of -2 as in Graph C.
