Question

if x+y-3xy=0 , x+z-5zx=0,y+z-4yz=0,then find 1/x+1/y+1/z

Answer 1

divided by xy in eqn. 1

1/y + 1/x = 3

divided by xz in eqn. 2

1/z + 1/x = 5

divided by yz in eqn. 3

1/z + 1/y = 4

now add three equation we get

2 (1/x + 1/y + 1/z ) = 12

1/x + 1/y + 1/z = 6