tolong di jawab ya soalnya besok di kumpul kakak kakak atau abang abang yg bisa

3) syarat gradien saling tegak lurus
m1 . m2 = - 1
a) 3x + 2y = 7
2y = - 3x + 7
m = -3/2
- 2x + 3y = 4
3y = 2x + 4
m = ⅔
m1 . m2 = - 3/2 . 2/3 = - 1 (benar)
b) 4y = 5x + 7
m = 5/4
- 4x + 5y + 2 = 0
5y = 4x - 2
m = 4/5
m1 . m2 = 5/4 . 4/5 = 1 (salah)
c) y = - 3x - 9
m = - 3
y = 3x + 5
m = 3
m1 . m2 = -3 . 3 = - 9 (salah)
d) y = 2x + 3
m = 2
y = ½ x - 12
m = ½
m1 . m2 = ½ . 2 = 1 (salah)
jadi pasangan yg saling tegak lurus adalah (A)

4) pers garis
(y - y1) / (y2 - y1) = (x - X1) / (x2 - X1)
(y + 3) / (2 + 3) = (x - 8) / (-2 - 8)
(y + 3) / 5 = (x - 8) / -10
- 10(y + 3) = 5 (x - 8)
- 10y - 30 = 5x - 40
- 10y = 5x - 40 + 30
- 10y = 5x - 10
- 2y = x - 2
y = - ½x + 1 (tdk ada opsi)