bantuin gue carinya....

Gradien garis a = m1 = -y/x = -3/-2 = 3/2
Gradien garis b = m2
a tegak lurus b :
m1 . m2 = -1 => 3/2 . m2 = -1 => m2 = -1 . 2/3 = -2/3

Persamaan garis b : m = -2/3 melalui (0, 3)
y - y1 = m (x - x1)
y - 3 = -2/3 (x - 0)
y - 3 = -2/3 x
2/3 x + y - 3 = 0 ===> kali 3
2x + 3y - 9 = 0

Bab Persamaan Garis
Matematika SMP Kelas VIII

garis a 
3x - 2y = 3 . (-2)
3x - 2y = -6

tegak lurus
ax + by = c, tegak lurus (p,q)
bx - ay = b . p - a . q

3x - 2y = -6, tegak lurus (0,3)
-2x - 3y = (-2) . 0 - 3 . 3
-2x - 3y = -9
2x + 3y - 9 = 0

jawabannya D