[Vadevalor]

Here's 2 ways of resolving forces,well ,if the 2nd one is correct,then the other one is wrong? I'm asking this out of curiosity since there is only one answer given

[Stonebridge]

I assume you mean "adding" forces, not "resolving".
Also, if the force marked "f" is meant to be the sum of W and N, it's pointing in the wrong direction in both cases.

The resultant of two vectors, end to end, is the vector that joins the tail of the first vector to the head of the second.

In this diagram, the sum of AB plus CD is AD
not DA.

The 2nd diagram below is the correct case.
Your diagrams both show the incorrect 1st case.



Both diagrams are mathematical constructions made by shifting one of the forces from the original situation where the two forces would be acting at the same point.

[teachercol]

A lot of students mix up the diagram showing three vectors in equilibrium with the diagram showing the resultant of two vectors.