Let us understand that, two more points are said to be collinear if they all lie on a single straight line.

We have the position vectors as,

Since, a and b are collinear. We can draw a relation between and .

Putting the values of and , we get

Comparing L.H.S and R.H.S, we get

2 = –6λ

And –3 = mλ

We need to find the value of λ in order to find m.

We have

2 = –6λ

Putting the value of λ in equation –3 = mλ

⇒ m = 3 × 3

⇒ m = 9

Thus, the value of m = 9.