4 5/7 - (х - 6 3/7)= 2 6/7
х - 6 3/7= 4 5/7 - 2 6/7
х - 6 3/7= 1 6/7
х= 1 6/7+6 3/7
х= 7 9/7= 8 2/7
5)
19 28/34-(m+2 29/34)=12 15/34
19 28/34-m-2 29/34=12 15/34
19 28/34-2 29/34-12 15/34=m
m=4 15/34