Materi Vektor! Soal nomor 1 & 2 dengan cara....

1) diketahui : a = 6i - 12j dan b = 3i - 9j

a) a + 1/3 b
= (6i - 12j) + 1/3 (3i - 9j)
= (6i - 12j) + (i - 3j)
= 7i - 15j

b) 1/2 a - 1/2 b
= 1/2 (a - b)
= 1/2 ((6i - 12j) - (3i - 9j))
= 1/2 (3i - 3j)
= 3/2 i - 3/2 j

2) diketahui :
a = (4x + 2y) ...... b = (6)
...... (-x + 2y) .............. (1)

a = -b

(4x + 2y) = (-6)
(-x + 2y) .... (-1)

Eliminasi
4x + 2y = -6
-x + 2y = -1
---------------- --
5x = -5
x = -1

-x + 2y = -1
-(-1) + 2y = -1
2y = -2
y = -1

Jadi x = -1 dan y = -1

Vektor
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