<?php
 
$numtext = "АВУКЕ49Л 034 1345 УК441Р пва231а ава34в аа123у ААА443А 34134А -=-4534А";
 
$regexp = "/\\s/ui";
 
$numbers = preg_split($regexp, $numtext);
 
$regexp = "/\b[А,В,Е,К,М,Н,О,Р,С,Т,У,Х]{2}[0-9]{3}[А,В,Е,К,М,Н,О,Р,С,Т,У,Х]\b/ui";
 
foreach($numbers as $number)
{
	echo (preg_match($regexp, $number)) ? "[+] {$number} правильный номер\n": "[-] {$number} неправильный номер\n";
}

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