The title of your post should be, "What do these two sentences mean?" <i>These </i> is the plural of <i> this </i>. Beware of copying the stupid professional speakers, who will often say, "These kind of polls" instead of "this kind of poll." Also, "two sentence" is plural, so it should be "two sentences."
When asking a question, we have to use "do mean" or "does mean" instead of "What mean?" or "What means?"