Narada Purana (Jyotisha Selections) · by Vyasa
Chapter 2 · Signs, Planets, Birth
जातकम् १
लग्नेऽशुभेज्यौ ग्लौदृष्टौ मृत्यौ कश्चन चाकृतिः ।धर्मांगस्थेशनौ शुक्रे केंद्रेऽब्जे व्ययधर्मगे ॥ ११६ ॥
In the full Narada Purana (Purva Bhaga) this is chapter 55, verse 116.
A bad planet and Jupiter may be in the lagna (rising sign), looked at by the Moon. With any planet in the 8th, life may be shortened to 22 years. Saturn may be in the 9th or the lagna. Venus may be in a corner house, the Moon in the 12th or 9th. (Our text is unclear here: the number word 'akriti', read as 22.)
Simple meaning: Some placements may shorten life to 22 years, others give long life.
शताब्दं गीष्पतौ कर्के कंटकस्थसितेज्ययोः ।
Jupiter in Cancer with these placements gives forty years. Another rule gives a hundred.
लग्ने शेष्टमगेष्टेशे तनुस्थे पंचवत्सरम् ।
Lagna and 8th lords swapped may shorten life to five years. Another placement gives fifty.
एतद्योगजमायुः स्यादथ स्पष्टमुदीर्यते ।
The exact life is worked out with a method that follows the strongest of the Sun and Moon.