Tentukan persamaan garis yang melalui: 1. Titik (1, -2) sjajar dngan garis y=-2x+7 2. Titik (-3, 5) sjajar dngan garis -5y=x-9 3. Titik (2, 3) tgak lurus dgn gr

1) y = - 2x + 7
m = - 2
sejajar m1 = m2 = - 2
pers garis
y - y1 = m ( x - X1 )
y + 2 = - 2 ( x - 1)
y = - 2x + 2 - 2
y = - 2x

2) - 5y = x - 9
m = 1 / - 5
m = - 1/5
sejajar m1 = m2 = - 1/5
pers garis
y - y1 = m ( x - X1 )
y - 5 = - 1/5 ( x + 3)
y = - 1/5 x - 3/5 + 5 ( dikali 5)
5y = - x - 3 + 25
5y = - x + 22

3) y = - 5x + 2
m = - 5
tegak lurus
m1 . m2 = - 1
- 5 . m2 = - 1
m2 = - 1 / - 5
m2 = 1/5
pers garis
y - y1 = m ( x - X1 )
y - 3 = 1/5 ( x - 2)
y = 1/5 x - 2/5 + 3 ( dikali 5)
5y = x - 2 + 15
5y = x + 13

4) 3y = 9x + 5
m = 9/3
m = 3
gradien tegak lurus
m1 . m2 = - 1
3 . m2 = - 1
m2 = - ⅓
pers garis
y - y1 = m ( x - X1 )
y - 3 = - ⅓ ( x + 3)
y = - ⅓x - 1 + 3
y = - ⅓ x + 2 ( dikali 3)
3y = - x + 6