It is not clear what you are asking, as there is no equation provided and the question is somewhat difficult to understand. In general, substituting a value for a variable in an equation means replacing the variable with the given value wherever it appears in the equation. For example, if the equation is "x + 5 = 10," and we substitute 3 for x, we would get "3 + 5 = 10." In this case, the resulting equation is a true statement, because 3 + 5 does indeed equal 10.