№ 1. Решите уравнения: 1) 5y + 27 = 4y + 21 2) 7y - 11 = 10y + 16 3) 4 · (0,7y - 4) = 3 · (−0,2y + 6) 4) \(\frac{5}{6}\)y - \(\frac{3}{4}\)y + 1 = \(\frac{2}{3}\)y - \(\frac{1}{6}\)

Решение уравнений:

1. 
   

   5y + 27 = 4y + 21

   
   

   5y - 4y = 21 - 27

   
   

   y = -6

   
   

   Ответ: y = -6

   
   


2. 
   

   7y - 11 = 10y + 16

   
   

   7y - 10y = 16 + 11

   
   

   -3y = 27

   
   

   y = \(\frac{27}{-3}\)

   
   

   y = -9

   
   

   Ответ: y = -9

   
   


3. 
   

   4 \(\cdot\) (0,7y - 4) = 3 \(\cdot\) (-0,2y + 6)

   
   

   2,8y - 16 = -0,6y + 18

   
   

   2,8y + 0,6y = 18 + 16

   
   

   3,4y = 34

   
   

   y = \(\frac{34}{3,4}\)

   
   

   y = 10

   
   

   Ответ: y = 10

   
   


4. 
   

   \(\frac{5}{6}\)y - \(\frac{3}{4}\)y + 1 = \(\frac{2}{3}\)y - \(\frac{1}{6}\)

   
   

   Приведем к общему знаменателю 12:

   
   

   \(\frac{10}{12}\)y - \(\frac{9}{12}\)y + 1 = \(\frac{8}{12}\)y - \(\frac{2}{12}\)

   
   

   \(\frac{1}{12}\)y + 1 = \(\frac{8}{12}\)y - \(\frac{2}{12}\)

   
   

   \(\frac{1}{12}\)y - \(\frac{8}{12}\)y = -\(\frac{2}{12}\) - 1

   
   

   -\(\frac{7}{12}\)y = -\(\frac{14}{12}\)

   
   

   y = \(\frac{-14/12}{-7/12}\)

   
   

   y = 2

   
   

   Ответ: y = 2