What does it mean if am equation is equivalent to 0=0? explain.

This means it has infinite solutions congrats. When solving algebraic equations you can find one solution, no solutions. When you have infinite solutions that means that equations has multiple things that can equal it.

It means that the equation always holds, no matter what the value of the unknown variable (x) is. Anything identity like 0=0 or 1=1, etc. leads to the same conclusion.

In other words there are infinitely many solutions.

To understand more you can always expand these identities by the usual multiplicaiton/addition to introduce x like this

1=1

x=x

2x=2x

2x+1=2x+1

etc.

and see that for any value x the equation holds because both sides are always the same.