Find the value of k for which thepoints A(1, -1), B(2, k) and C(4, 5) are collinear.
Since they are collinear, the area will be 0
→
Expanding with C3
→ 0 = (10-4k)-(5+4)+(k+2)
→ 0=-3k+3
→ 3k=3
∴ k= 1