Latihan UN SMP 2017 [HKM] [Matematika] Jawablah soal SPLDV pada gambar terlampir. Buatlah pembahasan yang jelas, lengkap, terperinci. ____________________ Kunju

3/4x + 1/6y = 4
____________ × 12
Persamaan (1) = 9x + 2y = 48

1/2x - 2/3y = -2
____________ × 6
Persamaan (2) = 3x - 4y = -12

9x + 2y = 48 [×3]
3x - 4y = -12 [×9]
______________
27x + 6y = 144
27x - 36y = -108
______________ _
42y = 252
y = 252/42 = 6

Substitusi ---> 3x - 4y = -12
3x - 4(6) = -12
3x - 24 = -12
3x = -12 + 24
3x = 12
x = 12/3 = 4

Maka nilai 2x - y adalah :
2(4) - 6 = 8 - 6 = 2

Jawabannya Adalah B.2

¾ x + 1/6 y = 4 | x 2
½ x - ⅔ y = -2 | x ½
________________
3/2 x + ⅓ y = 8
¼ x - ⅓ y = -1
____________+
3/2 x + ¼ x = 8 + (-1)
6/4 x + ¼ x = 8 - 1
7/4 x = 7x = 7 x 4/7 = 4
¾ x + 1/6 y = 4
¾ (4) + 1/6 y = 4
3 + 1/6 y = 4
1/6 y = 1
y = 6
2x - y = 2(4) - 6 = 8 - 6 = 2
jawabanya B