Kunci Jawaban Matematika Kelas 8 SMP/MTs Halaman 54 Persamaan Linier Dua Variabel, Kurikulum Merdeka

(1) 19x - 105y = 200
19x - 105x (-1) = 200
19x + 105 = 200
19x = 100 - 105
19x = 95
x = 5

Penyelesaian: x = 5 dan y = -1

(3) { 2/3x - y/7 = -5
{ 3x + 2y
________ = -1
4

Jawaban :

2/3x - y-7 = -5
2/1x x 7 - y/1 x 3 = -5 x 21
14x - 3y = -105 ... (1)

3x + 2y
_______ = -1
4
3x + 2y = -1 x 4
3x + 2y = -4 ... (2)

Persamaan (1) dan (2) :

14x - 3y = -105
3x + 2y = -4

28x - 6y = -210
9x + 6y = -12
________________ +
37x = -222
x = -6

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

-18 + 2y = -4
2y = -4 + 18
2y = 14
y = 7

Penyelesaian: x = -6 dan y = 7

(4) 5x - 3y + 1 = 4x - 2y = 10 - 6x + 3y

Jawaban :

Persamaan (1) dan (2) :

5x - 3y + 1 = 4x - 2y
5x - 4x - 3y + 2y = -1
x - y = -1 ... (4)

Persamaan (2) dan (3) :

4x - 2y = 10 - 6x + 3y
4x - 2y + 6x - 3y = 10
10x - 5y = 10 ... (5)

Persamaan (4) dan (5) :

x - y = -1
10x - 5y = 10

5x - 5y = -5
10x - 5y = 10
_______________ -
- 5x = -15
x = 3

(4) x - y = -1
3 - y = -1
3 + 1 = y
4 = y