Question

4r-2=4r-2 what's the solution? can have either have many solutions or none

Answer 1

That "equation" has an infinite number of "solutions", because
no matter what 'r' is, it's always a true statement.

The statement is equivalent to saying "I am I." or "You are you."

Answer 2

The answer should be 0
4r-2=4r-2
= minus 4r from both sides leaving -2=-2 and then add 2 to both sides leaving 0=0
Answer 0=0