Решите уравнение пожалуйста

(2 2/3 * х + 1 3/7 * х) * 21=58

(8/3 * х + 10/7 * х) * 21=58
х* (8/3 + 10/7) * 21=58
х* (7*8/7*3 + 3*10/3*7) * 21=58
х* (56/21 + 30/21) * 21=58
х*  86/21 * 21=58
х*  86/21 * 21/1=58
х* 86*21/21*1=58
х* 86/1=58
х* 86=58
х=58/86
х=2*29/2*43
х=29/43
Проверка
(2 2/3 * 29/43+1 3/7 * 29/43) * 21=29/43 * (8/3+10/7) * 21=
=29/43 * (7*8/3*7+3*10/3*7) * 21=29/43 * (56/21+30/21) *21=
=29/43 * 86/21 * 21=29/43 * 86/21 * 21/1=29/43 *  86*21/21*1=
=29/43 * 86/1 = 29*86/43*1 = 29*2/1*1 = 58/1 = 58