=42 ⇒‌‌(p+q)(p+q−1)=42....(i) (p+q)2−(p+q)−42=0 ∴p+q=7,−6 Thus, p+q=7,p+q≠=−6 and ‌p−qP2=20 ⇒‌‌‌
(p−q)!
(p−q−2)!
=20 ⇒‌‌(p−q)(p−q−1)=20.....(ii) (p−q)2−(p−q)−20=0 p−q=5,−4 p−q=5,p−q≠−4 Solving the two equations p+q=7 and p−q=5, we get p=6,q=7