Tìm x: -7/12 - 3/5 - x = 3/4; 1/2 - ( x + 1/3 ) = 5/6; 1/2 - ( x - 5/6 ) = 1/4

-7/12 - 3/5 - x = 3/4 

1/2 - ( x + 1/3 ) = 5/6 
1/2 - ( x - 5/6 ) = 1/4
3/35 - ( 3/5 - x ) = 2/7 
11/12 - ( 2/5 + x ) = 2/3