persamaan garis yang malalui titik A (3,-2) dan tegak lurus garis 2x +4y = 15 adalah

2x + 4y = 15
m = -x /y
= -2/4
= -1/2

Tegak lurus , m1 x m2 = -1
-1/2 x m2 = -1
m2 = -1 ÷ (-1/2)
m2 = -1 × -2/1
m2 = 2 , melewati ( 3 , -2)

y - y1 = m(x - x1)
y - (-2) = 2(x - 3)
y + 2 = 2x - 6
0 = 2x - 6 - y - 2
2x - y - 8 = 0

Bab Persamaan Garis
Matematika SMP Kelas VIII

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

2x + 4y = 15, tegak lurus, (3,-2)
4x - 2y = 4 . 3 - 2 . (-2)
4x - 2y = 12 + 4
4x - 2y = 16
2x - y = 8

y = 2x - 8