explain H X+M OH- MX HOH ???

This is a type of neutralisation reaction, where HX is an acid and MOH is a base. As we know that, when an acid reacts with a base, they neutralise each other by form salt of metal and water as represented by the follwoing reaction:

HX + MOH → MX + H₂O

For example HCl reacts with NaOH to form NaCl and water. In this reaction;

HX = HCl

MOH = NaOH

MX = NaCl

so,

HCl + NaOH → NaCl + H₂O