Forty and two years old was Ahaziah when he began to reign, and he reigned one year in Jerusalem. His mother's name also was Athaliah the daughter of Omri. Forty and two years old was Ahaziah - See the note on 2 Kings 8:26. Ahaziah might have been twenty-two years old, according to 2 Kings 8:26 (note), but he could not have been forty-two, as stated here, without being two years older than his own father! See the note there. The Syriac and Arabic have twenty-two, and the Septuagint, in some copies, twenty. And it is very probable that the Hebrew text read so originally; for when numbers were expressed by single letters, it was easy to mistake מ mem, Forty, for כ caph, Twenty. And if this book was written by a scribe who used the ancient Hebrew letters, now called the Samaritan, the mistake was still more easy and probable, as the difference between caph and mem is very small, and can in many instances be discerned only by an accustomed eye.
The reading in 2 Kings 8:26 is right, and any attempt to reconcile this in Chronicles with that is equally futile and absurd. Both readings cannot be true; is that therefore likely to be genuine that makes the son two years older than the father who begat him? Apage hae nugae!