Is it possible to have the same output (y) for two different inputs (x) in any solution set? For example: (2,9), (6,9). How do you know? Write your answer and explanation on the back on this paper.

Yes

Step-by-step explanation:

Yes it is possible to get the same output by providing two different inputs in a solution.

For example :

Let a function,  ......(1)

Case 1

let x = -2, putting the value of x in equation (1), we get

   = 4

Case 2

let x = 2, putting the value of x in equation (1), we get

  = 4

Therefore, for both the different input (x), we get the same output (y).

not only in mathematics, scientific proof also are required in the other field of science. also maths proofs are of particular structure, containing steps and logics. so proving is like doing science, it is science. that's why it is important to prove. 

an inaccurate proof leads to errors, or stating results that are not accurate.  which wil mess the probelm up you dont want this