The error in Misha's proof is in Step 3. The key step that she incorrectly made is the assumption that two distinct lines with the same slope must have a point of intersection.
In reality, if two lines are distinct and have the same slope, they cannot intersect at any point; this is precisely the definition of parallel lines. Therefore, Misha's claim that since they are assumed to not be parallel, they must intersect, is incorrect.
Consequently, Misha's statement and reasoning lead to a contradiction that does not accurately reflect the relationship between distinct lines with the same slope. Thus, the correct response is:
Step 3 is incorrect. The lines do not need to have a point of intersection since they are not parallel.