a x b = c x a
a x b - c x a = 0
a x b + a x c = 0
a x (b + c) = 0
=> a // (b+c)
a = lambda (b + c)

… property of cross product ... if 2 vectors have cross product equal 0, the 2 vectors must be parallel.

Okay, will do. Thank you ! Can u help me mark it as the question is answered ? Thank you!

the system automatically marks the question as answered when someone UPLOADS an answer in an image file.

since the answer for this question involves just a few lines, I thought I just type it in a short comment instead.

Yep but i can't upload another question if it remains as pending :(

sorry, I did not realise that the system has such a restriction … makes good sense … thanks for letting me know.

I have uploaded a proper answer so now you can post more questions ...

if someone does this to you again, I believe the other thing you can do is delete your own question entirely, then you can upload a new question.

Yep, will do ! Thank you very much for your help ! I really appreciate it !! :))