Question

Diketahui sistem persamaan linear (1/x) +
(2/y)= 11 dan (3/x) - (5/y)=11, Maka nilai dari
(x.y) adalah?

Answer 1

Jika a = 1/x
       b = 1/y

maka pers itu diubah sementara
a + 2b = 11 --> x3 untuk menyamakan koefisien a
3a - 5b = 11

3a+6b =33
3a -5b=11
---------------- -
     11b = 22
         b = 2

a+2b = 11
      a = 11-2b
         = 11-2.2
         = 11-4 
         = 7

a=7 --> 7 = 1/x --> x = 1/7
b= 2 --> 2 = 1/y --> y= 1/2

x.y = 1/7. 1/2 = 1/14

Answer 2

1/x + 2/y = 11 (x3) --> 3/x + 6/y = 33
3/x - 5/y = 11 (x1) --> 3/x - 5/y = 11 _
                                       11/y = 22
                                           y = 1/2
1/x + 2/(1/2) = 11
1/x = 11 - 4
1/x = 7
x = 1/7

x.y = 1/7 x 1/2 = 1/14