Your K-map seems to be o.k.
Equation 1 represents the K-map correctly, so do then NAND form and the schematic.
The only thing that irritates me is your way of writing an negated variabel as X´. I'd use an overbar, as you did for the negation in the NAND equation. But that may be totally correct if you've been taught so. These details tend to differ in different parts of the world.