1)10: 1 7/8=8x-2x-3x 2)3 2/45x+1 7/30x=6 1/9 3)(8 2/5: x+3 5/9): 4 1/6=1 1/3 4)(5 1/6-x)•2 7/10-1 3/14=3 2/7

10 : 1 ( 7/8 ) = 8X - 2X - 3X 
10 : ( 15/8 ) = X * ( 8 - 2 - 3 ) 
80/15 = X * 3 
X = ( 16/3  ) : 3 
X = 16/9 
X = 1 ( 7/9 ) 

3 ( 2/45 ) X + 1 ( 7/30 ) X = 6 ( 1/9 ) 
(137/45 ) X + ( 37/30 ) X = 55/9
( 274/90 ) X + ( 111/90 ) X = 550/90 
274X + 111X = 550 
385X = 550 
X = 1 ( 165/385 ) 
X = 1 ( 33/77 )
X = 1 ( 3/7 )

( 8 2/5 : X + 3 5/9 ) : 4 ( 1/6 ) = 1 ( 1/3 )
8 ( 2/5 ) : X + 3 ( 5/9 ) = 1 ( 1/3 ) * 4 ( 1/6 ) 
8 ( 2/5 ) : X + 3 ( 5/9 ) = ( 4/3 ) * ( 25/6 ) 
8 ( 2/5 ) : X + 3 ( 5/9 ) = 50/9 
8 ( 2/5 ) : X = 5 ( 5/9 ) - 3 ( 5/9 ) 
8 ( 2/5 ) : X = 2 
X = 8 ( 2/5 ) : 2 
X = 8,4 : 2 
X = 4,2 

( 5 1/6 - X ) * 2 ( 7/10 ) - 1 ( 3/14 ) = 3 ( 2/7 ) 
( 5 1/6 - X ) * 2 ( 7/10 ) = 3 ( 2/7 ) + 1 ( 3/14 ) 
( 5 1/6 - X ) * 2 ( 7/10 ) = 3 ( 4/14 ) + 1 ( 3/14 ) 
( 5 1/6 - X ) * 2 ( 7/10 ) = 4 ( 1/2  ) 
5 ( 1/6 ) - X = 4 ( 1/2 ) : 2 ( 7/10 ) 
5 ( 1/6 ) - X = ( 9/2 ) : ( 27/10 ) 
5 ( 1/6 ) - X  = 1 ( 2/3 ) 
X = 5 ( 1/6 ) - 1 ( 2/3 ) 
X = 4  ( 7/6 ) - 1 ( 4/6 ) 
X = 3 ( 1/2 )