Let x and y denote the number dog and cat owners, respectively, in a city,
where x > y. If possible, determine which of the expressions in each pair is larger?
Interpret each of the expressions in terms of populations. Justify your reasoning.
PAIR 1: x+y and 2y
PAIR 2: Hy and xxx
PAIR 3: ) and is

For this case we have the following equation:
 y = 12
 This line is a horizontal line whose cut point with the y axis is equal to 12.
 The slope of a horizontal line is equal to zero.
 Then, the slope of a parallel line is equal to the slope of the original line, therefore, the slope is equal to zero.
 The slope of a perpendicular line is:
 
 Where,
 m: slope of the original line
 Substituting values:
 
 m' = ∞
 Therefore, the slope of the perpendicular line tends to infinity.
 
 For the line y = 12 the slopes of the parallel and perpedicular lines are:
 Parallel: m = 0
 Perpendicular: m' = ∞