4.how can you verify euler’s formula for this net of a cube?

This is for any polyhedron that does not intersect itself. The Euler's formula states that the number of faces plus the number of vertices or corner points less the number of edges is always equal to 2.

Faces + Vertices - Edges = 2

A cube has 6 faces, 8 vertices, and 12 edges.

Euler's formula: 6 + 8 - 12 = 2 ⇒ 14 - 12 = 2 ⇒ 2 = 2 ur welcome man