А)
(6 3/14 - х) * 2*3+1/3 = 9 5/6
(6 3/14 - х) * 7/3 = 9 5/6
(6 3/14 - х) * 7/3 = 9*6+5/6
(6 3/14 - х) * 7/3 = 59/6
(6*14+3/14 - х) * 7/3 = 59/6
87/14 * 7/3 - х * 7/3= 59/6
29/2 * 1 - х * 7/3= 59/6
29/2 - х * 7/3 = 59/6
29/3 - х = 59/6 : 7/3
29/3 - х = 4 3/14
х=2