Question

Tentukan nilai a agar garis 2x+ay=-3 sejajar dengan garis x-3y+20=0

Answer 1

2x + ay = - 3
ay = - 2x - 3
y = (-2/a)x - 3/a
m₁ = - 2/a

x - 3y + 20 = 0
3y = x + 20
y = (1/3)x + 20/3
m₂ = 1/3

agar sejajar maka 
m₁ = m₂
- 2/a = 1/3
- 6 = a

Answer 2

syarat garis sejajar :
m1 = m2
maka x-3y = -20
-3y = -20-x
3y = 20+x
y = 1/3x+6 2/3
maka m = 1/3
jadi 1/3 = 1/3
m2 = 1/3
2x+ay = 1/3
ay = -3-2x
ay = -2x-3
-2/a = 1/3
a = 6