А)Х+(3,1/2+5,5/8)=20 Б)X-(12.1/5-7.4/15)=5.2/5 В)100-Х=14,3/5+214/5 Г)21,3/5-Х=4,3/10+5,1/2

А) Х + (3 1/2 + 5 5/8) = 20;

Х = 20 - (5 * 8 + 5)/8 - (3 * 2 + 1)/2 = 20 * 8/8 - 45/8 - 4 * 7/8 = 160/8 - 45/8 - 28/8 = (160 - 45 - 28)/8 = 87/8;

Ответ: Х = 87/8.

Б) X - (12 1/5 - 7 4/15) = 5 2/5;

Х = (5 * 5 + 2)/5 + (12 * 5 + 1)/5 - (7 * 15 + 4)/15 = 27/5 + 61/5 - 109/15 = 81/15 + 183/15 - 109/15 = (81 + 183 - 109)/15 = 155/15 = 31/3;

Ответ: 31/3.

В) 100 - Х = 14 3/5 + 214/5;

Х = 100 - (14 * 5 + 3)/5 - 214/5 = 500/5 - 73/5 - 214/5 = (500 - 73 - 214)/5 = 213/5;

Ответ: Х = 213/5.

Г) 21 3/5 - Х = 4 3/10 + 5 1/2;

Х = 21 3/5 - 4 3/10 - 5 1/2 = (21 * 5 + 3)/5 - (4 * 10 + 3)/10 - (5 * 2 + 1)/2 = 108/5 - 43/10 - 11/2 = 216/10 - 43/10 - 55/10 = 118/10;

Ответ: 118/10.