The answer to your question is,
Each time they assume the sum is rational; however, upon rearranging the terms of their equation, they get a contradiction (that an irrational number is equal to a rational number). Since the assumption that the sum of a rational and irrational number is rational leads to a contradiction, the sum must be irrational.
-Mabel <3
If you think about this equation as a line, then in order to have an infinite number of solutions is to have another equation that describes the same line.
So, for example 3y=2x-15 would be one of those.
Answer:
That is incorrect. It would be appropriate if the median were 79.3, since the median is the value in the middle (when placing the data in order).