persamaan garis yang melalui titik potong dua garis 3y+x=5 dan 2y= -x+4 dengan dua garis y=x+2 dan 2y= - x -2 adalah.... A.x- 4y= - 2 B.x- 4y= 2 C.2x-3y=1 D..2x

Kelas 8 Matematika
Bab Persamaan Garis

2y = -x + 4
2y + x = 4

3y + x = 5
2y + x = 4
--------------- -
y = 1

2y + x = 4
2 . 1 + x = 4
x = 4 - 2
x = 2

(2, 1)

y = x + 2

2y = -x - 2
2 (x + 2) = -x - 2
2x + 4 = -x - 2
2x + x = -2 - 4
3x = -6
x = -6/3
x = -2

y = x + 2
y = -2 + 2
y = 0

(-2, 0)

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(2, 1) dan (-2, 0)

(y - y1) / (y2 - y1) = (x - x1) / (x2 - x1)
(y - 1) / (0 - 1) = (x - 2) / (-2 - 2)
(y - 1)/(-1) = (x - 2)/(-4)
4 (y - 1) = 1 (x - 2)
4y - 4 = x - 2
x - 4y = -4 + 2
x - 4y = -2