Hello there!

Greetings!

It's quite easy,  since both the vectors are parallel then for cetain value of a , we have,

i + 2j -3k= a (3i + mj -9k)...........(1)

Or, -3k = -9a k ( on equating k component of both the sides of the equation 1. )

or a =3 .....(2)

Also , 2j = ma j ( on equating j component of both the sides of equation 1.)

or 2j = m × 3×j (on putting the value a from 2) ,

or  m = 2/3 .

Thus , m = 2/3.

Thankyou