Titik A (x,3,5) , B (4,y,1) dan C (2,5,9) terletak pada suatu garis lurus, maka x + y ...

Mapel : Matematika
Kelas : X SMA
Bab : Vektor

Pembahasan :
AB = k . BC
b - a = k [c - b]
[(4 - x), (y - 3), -4] = k [-2 , (5 - y) , 8]

-4 = 8k
K = -1/2

4 - x = -2k
4 - x = -2(-1/2)
4 - x = 1
x = 3

y - 3 = k(5 - y)
y - 3 = -1/2(5 - y)
y - 3 = -5/2 + y/2
y - (y/2) = -5/2 + 3
y/2 = 1/2
Y = 1

Maka...
X + y = 3 + 1 = 4