Решить уравнение 16(7-4b)-14(4b+1)+10(8b-1)=38

16 * (7 - 4 * b) - 14 * (4 * b + 1) + 10 * (8 * b - 1) = 38; 

Разделим на 2. 

16 * (7 - 4 * b)/2 - 14/2 * (4 * b + 1) + 10/2 * (8 * b - 1) = 38/2;  

8 * (7 - 4 * b) - 7 * (4 * b + 1) + 5 * (8 * b - 1) = 19;  

8 * 7 - 8 * 4 * b - 7 * 4 * b - 7 * 1 + 5 * 8 * b - 5 * 1 = 19; 

56 - 32 * b - 28 * b - 7 + 40 * b - 5 = 19; 

(-32 * b - 28 * b + 40 * b) + (56 - 7 - 5) = 19; 

b * (40 - 32 - 28) + (56 - 12) = 19; 

b * (8 - 28) + 44 = 19; 

b * (-20) + 44 = 19; 

-20 * b + 44 = 19; 

-20 * b = 19 - 44; 

-20 * b = -25; 

20 * b = 25; 

b = 25/20; 

b = 5/4; 

b = 1 1/4; 

b = 1.25.