1)х-7 8/11=2 5/11 2)3 7/17-(х+1 4/17)=1 9/17

1) х - 7 8/11 = 2 5/11;

х - 85/11 = 27/11;

х = 27/11 + 85/11;

х = 112/11;

112/11 - 7 8/11 = 2 5/11;

112/11 - 85/11 = 27/11;

27/11 = 27/11. 

2) 3 7/17 - (х + 1 4/17) = 1 9/17;

58/17 - (х + 21/17) = 26/17;

-х - 21/17 = 26/17 - 58/17;

-х  - 21/17 = -32/17;

-х = -32/17 + 21/17;

-х = -11/17;

-х * (-1) = -11/17 * (-1);

х = 11/17;

3 7/17 - (11/17 + 1 4/17) = 1 9/17;

58/17 - (11/17 + 21/17) = 26/17;

58/17 - 32/17 = 26/17;

26/17 = 26/17.