Решите уравнения : а) 4,75-(х+2 3/8)=1 1/6 б) 9 5/28-(7 1/7-х)=2

а) 4,75 - (х + 2 3/8) = 1 1/6; 

х + 2 3/8 = 4,75 - 1 1/6; 

х + 2 3/8 = 475/100 - 7/6; 

х + 2 3/8 = 19/4 - 7/6; 

х + 2 3/8 = (19 * 3)/(4 * 3) - (7 * 2)/(6 * 2); 

х + 2 3/8 = 57/12 - 14/12; 

х + 2 3/8 = 43/12; 

х = 43/12 - 19/8; 

х = (43 * 2)/(12 * 2) - (19 * 3)/(8 * 3); 

х = 86/24 - 57/24; 

х = 29/24 = 1 5/24. 

Проверка: 

4,75 - (29/24 + 2 3/8) = 1 1/6;

475/100 - (29/24 + 19/8) = 7/6; 

19/4 - ((29/24 + (19 * 3)/(8 * 3)) = 7/6; 

19/4 - (29/24 + 57/24) = 7/6; 

19/4 - 86/24 = 7/6; 

19/4 - 43/12 = 7/6;

(19 * 3)/(4 * 3) - 43/12 = 7/6

57/12 - 43/12 = 7/6; 

14/12 = 7/6; 

7/6 = 7/6. Решение правильно. 

б) 9 5/28 - (7 1/7 - х) = 2 4/21; 

50/7 - х = 257/28 -  46/21 ; 

50/7 - х = (257 * 21)/(28 * 21) - (46 * 28)/(21 * 28); 

50/7 - х = 5397/588 - 1288/588; 

50/7 - х = 4109/588; 

50/7 - х = 587/84; 

х = 50/7 - 587/84; 

х= (50 * 12)/(7 * 12) - 587/84; 

х = 600/84 - 587/84; 

х = 13/84. 

Проверка: 

9 5/28 - (7 1/7 - 13/84) = 2 4/21; 

257/28 - (50/7 - 13/84) = 46/21; 

257/28 - ((12 * 50)/(7 * 12) - 13/84) = 46/21; 

257/28 - (600/84 - 13/84) = 46/21; 

257/28 - 587/84 = 46/21; 

(257 * 3)/(28 * 3) - 587/84 = 46/21; 

771/84 - 587/84 = 46/21; 

184/84 = 46/21; 

46/21 = 46/21. Решение правильно.