Решите уравнения: 5y + (8y+9) = 100 x - (50-x) = 12 4 (x-7) = 3x+5 - 5x+3 (3+2x) = 7

Найдем корни:

1) 5 * y + (8 * y + 9) = 100;

Скобки раскроем.

5 * y + 8 * y + 9 = 100;

y * (5 + 8) + 9 = 100;

y * 13 + 9 = 100;

13 * y + 9 = 100;

13 * y = 100 - 9;

13 * y = 81;

y = 81/13.

2) x - (50 - x) = 12;

x - 50 + x = 12;

2 * x - 50 = 12;

x - 25 = 6;

x = 6 + 25;

x = 31.

3) 4 * (x - 7) = 3 * x + 5;

4 * x - 4 * 7 = 3 * x + 5;

4 * x - 28 = 3 * x + 5;

4 * x - 3 * x = 5 + 28;

x = 33.

4) - 5 * x + 3 * (3 + 2 * x) = 7;

-5 * x + 3 * 3 + 3 * 2 * x = 7;

-5 * x + 9 + 6 * x = 7;

x + 9 = 7;

x = 7 - 9;

x = - 2.