vektor a=2i-3j+k,b=pi+2j-k,c=i-j+3k bila b & c tegak lurus.vektor a-b-c? tolong

VEKTOR

b tegak lurus c
b•c = 0
(p, 2, -1)•(1, -1, 3) = 0
p - 2 - 3 = 0
p - 5 = 0
p = 5
jadi b = 5i + 2j - k

Vektor a - b - c
=> (2, -3, 1) - (5, 2, -1) - (1, -1, 3)
=> (2-5-1, -3-2-(-1), 1-(-1)-3)
=> (-3-1, -5+1, 2-3)
=> (-4, -4, -1)
=> -4i - 4j - k