no 19 dan 20 bntuin kk, bserta caranya kak

Kelas 8 Matematika
Bab Persamaan Garis

19] Gradien = m

m = (y2 - y1)/(x2 - x1)
m = (4 - 3)/(2 - (-1))
m = 1/3

Sejajar, maka m1 = m2 = 1/3

ax + by + c = 0
m = -a/b

ax + 6y + 7 = 0
1/3 = -a/6
a = -6/3
a = -2

-3/2 . a
= -3/2 . (-2)
= 3

20] ax + by + c = 0, tegak lurus, (p, q)
bx - ay - (bp - aq) = 0

3x + 2y - 7 = 0, tegak lurus, (1, -2)
2x - 3y - (2 . 1 - 3 . (-2)) = 0
2x - 3y - (2 + 6) = 0
2x - 3y - 8 = 0