Question

Himpunan penyelesaian

Answer 1

6/x + 3/y = 21
7/x - 4/y = 2

misalkan
1/x = a
1/y = b

maka
6a+3b=21
7a-4b=2
--------------- elim b
24a+12b=84
21a-12b=6
--------------- +
45a= 90
a = 2

substitusi
6a+3b=21
6(2)+3b=21
3b=9
b=3

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

b = 1/y
3 = 1/y
y = 1/3

6xy = 6(1/2)(1/3)
= 1 (c)