diketahui a= 2i - j, b=-2i+3j r=8i-6j jika r=ka+mb ditanya k+m?

Vektor
Kelas X

r = ka + mb
(8 , -6) = k(2 , -1) + m(-2 , 3)
(8 , - 6) = (2k , -k) + (-2m , 3m)
(8 , -6) = (2k - 2m , -k + 3m)

Didapat
2k - 2m = 8 | : 2 |
⬇ ⬇ ⬇ ⬇ ⬇ ⬇
k - m = 4
-k + 3m = -6
_________ (+)
2m = -2
m = - 1

Sehingga
k - m = 4
k - (-1) = 4
k = 3

k + m
= 3 - 1
= 2