The correct option is A abc + 3(a + b + c) = ab + bc + ca
Given x=t3t−1,y=t2−3t−1, where t = a,b,c
If the three points are collinear, then they will satisfy the same equation Ax + By + C = 0.
⇒A(t3t−1)+B(t2−3t−1)+C=0
⇒At3+Bt2+Ct−(3B+C)=0, which is cubic equation in t
∴a+b+c=−BA
ab+bc+ca=+CA
abc=+(3B+CA)
⇒abc=+3(BA)+(CA)
abc=−3(a+b+c)+ab+bc+ca
∴ab+bc+ca=abc+3(a+b+c)