Решите уравнение а) 5y + ( 8y+9)=100; б) x-( 50-x)=12; в)

Вычислим корни.

а) 5 * y + (8 * y + 9) = 100; 

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

14 * y + 9 = 100;

14 * y = 100 - 9;

14 * y = 81;

y = 81/14; 

б) x - (50 - x) = 12; 

x - 50 + x = 12;

2 * x - 50 = 12;

2 * x = 12 + 50;

x = 6 + 25;

x = 31.

в) ( 18 - 3 * x) - (4 + 2 * x) = -6; 

18 - 3 * x - 4 - 2 * x = -6;

-5 * x + 14 = -6;

-5 * x = -6 - 14;

5 * x = 21;

x = 21/5.

г) x + (x + 1) + (x + 2) = 9; 

x + x + 1 + x + 2 = 9;

3 * x + 3 = 9;

3 * x = 9 - 3;

3 * x = 6;

x = 6/3;

x = 2.

д) (z - 2) + (z - 1) + z = -3; 

z - 2 + z - 1 + z = -3;

2 * z - 3 = -3;

z = 0.

е) 21 + (20 - 4 * x) - (11 - 2 * x) = 0; 

21 + 20 - 4 * x - 11 + 2 * x = 0; 

-2 * x + 9 + 21 = 0; 

-2 * x + 30 = 0; 

2 * x = 30; 

x = 15.