The equations of PQ and PR are given by ‌y−1=‌
−2∓tan‌45∘
1±(−2)‌tan‌45∘
(x−2) ‌⇒‌‌y−1=(‌
−2∓1
1±2
)(x−2) ‌⇒‌‌y−1=−‌
1
3
(x−2) ‌‌ and ‌‌‌y−1=3(x−2) ‌⇒‌‌x+3y=5‌ and ‌3x−y=5 The combined equation of these two lines is (x+3y−5)(3x−y−5)‌=0 ⇒3x2−3y2+8xy−20x−10y+25‌=0