Решить уравнения (х+2 3/13) - 1 7/26 = 4 5 / 398 7/18 - (1 11/15+у) = 3 4/15+2 13/45 найди значение выражения наиболее удобным способом 2 9/49 + (7 3/85 + 3 40/49) (5 16/39 + 1 6/11) - 2 16/397 13/14 - (2 13/14 + 4 17/25)

Решаем уравнения с одной переменной:

1) (х + 2 3/13) - 1 7/26 = 4 5/39;

Раскрываем скобки:

х + 2 3/13 - 1 7/26 = 4 5/39;

х + 2 6/26 - 1 7/26 = 4 5/39;

х + 1 32/26 - 1 7/26 = 4 5/39;

х + 25/26 = 4 5/39;

х = 4 5/39 - 25/26;

х = 4 10/78 - 75/78;

х = 3 88/78 - 75/78;

х = 3 13/78;

х = 3 1/6;

Проверяем:

(3 1/6 + 2 3/13) - 1 7/26 = (3 13/78 + 2 18/78) - 1 7/26 = 5 31/78 - 1 21/78 = 4 10/78 = 4 5/39.

2) 8 7/18 - (1 11/15 + у) = 3 4/15 + 2 13/45;

8 7/18 - 1 11/15 - у = 3 4/15 + 2 13/45;

8 7/18 - у = 3 4/15 + 1 11/15 + 2 13/45;

8 7/18 - у = 4 15/15 + 2 13/45;

у = 8 7/18 - 5 - 2 13/45;

у = 3 7/18 - 2 13/45;

у = 3 35/90 - 2 26/90;

у = 1 9/90;

у = 1 1/10;

Проверяем:

8 7/18 - (1 11/15 + 1 1/10) = 3 4/15 + 2 13/45;

8 7/18 - (1 22/30 + 1 3/30) = 3 12/45 + 2 13/45;

8 7/18 - 2 25/30 = 5 25/45;

8 7/18 - 2 5/6 = 5 25/45;

8 35/90 - 2 75/90 = 5 25/45;

7 125/90 - 2 75/90 = 5 25/45;

5 50/90 = 5 5/9;

5 5/9 = 5 5/9.

Находим значение математического выражения наиболее удобным способом:

1) 2 9/49 + (7 3/85 + 3 40/49) = 2 9/49 + 7 3/85 + 3 40/49 = 7 3/85 + 5 49/49 = 7 3/85 + 6 = 13 3/85;

2) (5 16/39 + 1 6/11) - 2 16/39 = 5 16/39 + 1 6/11 - 2 16/39 = 3 + 1 6/11 = 4 6/11;

3) 7 13/14 - (2 13/14 + 4 17/25) = 7 13/14 - 2 13/14 - 4 17/25 = 5 - 4 17/25 = 4 25/25 - 4 17/25 = 8/25.