Narada Purana (Jyotisha Selections) · by Vyasa
Chapter 2 · Signs, Planets, Birth
जातकम् १
शुभैर्दृष्टः सवीर्योंगे केंद्रस्थे चायुरर्थदः ।स्वच्चोब्जे स्वर्क्षगैः सौम्यैः सवीर्यैंगाधिपे तनौ ॥ ११२ ॥
In the full Narada Purana (Purva Bhaga) this is chapter 55, verse 112.
A strong planet may be in the lagna (rising sign) or a corner house, looked at by good planets. It gives long life and wealth. The Moon may be in its high sign. Good planets may be strong in their own signs. The strong lagna lord may be in the lagna.
Simple meaning: Strong planets in good places give long life and wealth.
षष्ट्यब्दकेंद्रसौम्येभेष्टशुद्धे सप्ततिर्गुरौ ।
Good planets in corner houses with a clear 8th give seventy years. Sixty and eighty come from other placements.
लग्नाधिपे बलयुतशीत्यब्दं त्वायुरीरितम् ।
Strong lagna lord with good planets well placed gives eighty years of life.
लयेशे धर्मगेजीवेष्टस्थे क्रूरेक्षिते जिताः ।
The lagna lord and 8th lord together in the 8th may shorten life to 27 years.