Tolong bantu jawab no 9

proyeksi orthogonal vektor a pada b 

|c| = [tex] \frac{a . b}{|b|} [/tex]
4/3 = [tex] \frac{(m, -6, -3) . (2, 1, -2)}{ \sqrt{2^2 + 1^2 + 2^2} } [/tex]
4/3 = [tex] \frac{2m + (-6) + 6}{ \sqrt{9} } [/tex]
4/3 = 2m/3
2m = 4
m = 2