Question

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Giúp mình với :

Answer 1

[tran vinh]

xy/x+y=12/7 suy ra x+y/xy=7/12 suy ra 1/x+1/y=7/12

tương tự: 1/y+1/z=-1/6,1/z+1/x=-1/4

ta có: 1/x+1/y+1/y+1/z+1/z+1/x=7/12+-1/6+-1/4

2(1/x+1/y+1/z)=1/6

1/x+1/y+1/z=1/12

mà 1/y+1/z=-1/6

suy ra 1/x+-1/6=1/12

suy ra 1/x=1/4

suy ra x=4

thay  1/x=1/4 vào 1/x+1/y=7/12,1/z+1/x=-1/4

1/4+1/y=7/12 suy ra 1/y=1/3 suy ra y=3

1/z+1/4=-1/4 suy ra 1/z=-1/2 suy ra z=-2

vậy x=4,y=3,z=-2