Question

tolong no 6 dan 7... pakai caranya

Answer 1

6).
a(x,2,-1)
b(4, -3,6)
c(2,0,3)

a dan b tegak lurus --> a.b = 0
4x -6 - 6 = 0
x = 3
maka  a(3,2,-1)

3a - b + 2c = (9,6,-3) - (4, -3, 6) + (4, 0, 6) =
= {(9-4+4) , (6+3 + 0), (-3-6+6) }
= (9, 9, - 3)