tolong jawab ya ........

vektor b-c = (-1,1,3) - (4,-1,4) = (-5,2,-1)
vektor a = (-4,3,-4)

proyeksi ortogonal vektor a pada vektor (b-c)?

20 + 6 + 4 ( -5, 2, -1 )
= -----------------
( √25+4+1 )²
= 30/30 ( -5, 2, -1)
= ( -5, 2, -1 )
= -5i + 2j -k

Jawabannya A.