tentukan PGL melalui (-2,1) dan tegak lurus dengan garis yg melalui titik (-5,-4) dan (0,-2)

Bab Persamaan Garis
Matematika SMP Kelas VIII

(-5, -4) dan (0, - 2)

(y - y1) / (y2 - y1) = (x - x1) / (x2 - x1)
(y - (-4)) / (-2 - (-4)) = (x - (-5)) / (0 - (-5))
(y + 4) / 2 = (x + 5) / 5
5 (y + 4) = 2 (x + 5)
5y + 20 = 2x + 10
2x - 5y = 20 - 10
2x - 5y = 10

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

2x - 5y = 10, tegak lurus, (-2, 1)
-5x - 2y = -5 . (-2) - 2 . 1
-5x - 2y = 10 - 2
-5x - 2y = 8
5x + 2y + 8 = 0