Question

Persamaan garis yang melalui titik (-3 , -3) dan sejajar garis 4x - 3y + 6 = 0 adalah ..

A. 4x - 3y + 1 = 0
B. 4x - 3y + 3 = 0
C. 3x - 4y + 21 = 0
D. -3x - 4y - 21 = 0

Answer 1

4x - 3y + 6 = 0
3y = 4x + 6
y = 4/3x + 2
m1 = 4/3

Sejajar, maka:
m2 = m1
m2 = 4/3

Persamaan garis yang melalui (-3, -3) dengan m2 = 4/3:
y - y1 = m2 . (x - x1)
y - (-3) = 4/3 . (x - (-3))
y + 3 = 4/3x + 4 (kali 3 kedua ruas)
3y + 9 = 4x + 12
3y = 4x + 12 - 9
3y = 4x + 3
0 = 4x - 3y + 3

Jawaban: B

Answer 2

Ax + by + c = 0
m = -a/b

4x -3y +6 = 0
m1 = -4/-3 = 4/3

karena //, maka m1 = m2 = 4/3

persamaan garis
y - y1 = m2(x - x1)
y -(-3)= 4/3(x - (-3))
y + 3 = 4/3(x + 3)
y + 3 = 4/3x +4
-4/3x + y -1 = 0. (dikalikan -3)

4x -3y + 3 = 0 B