Question

The points (p,q), (m,n)and (p-m,q-n) are Collinear prove that pn=qm.

Answer 1

Gn : Points are collinear
So, p[n-(q-n)] + m[(q-n)-q] + [(p-m)(q-n)] = 0
2pn-pq-mn+pq-mq-pn+mn = 0  ⇒                   
2pn-pn-mq =0 ⇒
pn-mq = 0 ⇒
pn=mq

Hence Proved