6/x + 12/y = 6 8/× + 8/y = 6 Nilai dari 2x+y=... A. 4 B. 8 C. 12 D. 16 / = per

Kelas 8 Matematika
Bab SPLDV

1/x = a
1/y = b

6a + 12b = 6 → dibagi 3 → 2a + 4b = 2
8a + 8b = 6 → dibagi 2 → 4a + 4b = 3

4a + 4b = 3
2a + 4b = 2
----------------- -
2a = 1
a = 1/2

2a + 4b = 2
2 . 1/2 + 4b = 2
4b = 2 - 1
b = 1/4

a = 1/2
1/x = 1/2
x = 2

b = 1/4
1/y = 1/4
y = 4

2x + y
= 2 . 2 + 4
= 4 + 4
= 8