Question

Tolong jawab dengan jalan soal nomor 3

Answer 1

3/x - 4/y = -6
2/x + 3/y = 13

3(1/x) - 4(1/y) = -6
2(1/x) + 3(1/y) = 13

misalkan 1/x = a dan 1/y = b
3a - 4b = -6 ...(1) x 2
2a + 3b = 13 ...(2) x 3

6a - 8b = -12
6a + 9b = 39
__________-
-17b = -51
b = -51/(-17) = 3

1/y = 3
y = 1/3

substitusi
2a + 3b = 13
2a + 3 . 3 = 13
2a + 9 = 13
2a = 13 - 9
2a = 4
a = 4/2 = 2

1/x = 2
x = 1/2

maka nilai dari 1/(x - y)
= 1/(1/2 - 1/3)
= 1/(3/6 - 2/6)
= 1/(1/6)
= 6

jawaban ada di pilihan A