№7. Реши уравнения: 1) -2,4 + a = -4; 2) -0,7b = -0,28; 3) 8 + (-x) = -3,5; 4) y - 1,7 = -6,2; 5) 2c(c + 6) = 0; 6) \(\frac{d}{-5,3}\) = 0,1; 7) |m| = 4; 8) \(\frac{2}{-k}\) = -3.

Решение:

1. 
   

   1) \( -2.4 + a = -4 \)
   \( a = -4 + 2.4 \)
   \( a = -1.6 \)

   
   

   2) \( -0.7b = -0.28 \)
   \( b = \frac{-0.28}{-0.7} \)
   \( b = 0.4 \)

   
   

   3) \( 8 + (-x) = -3.5 \)
   \( 8 - x = -3.5 \)
   \( -x = -3.5 - 8 \)
   \( -x = -11.5 \)
   \( x = 11.5 \)

   
   

   4) \( y - 1.7 = -6.2 \)
   \( y = -6.2 + 1.7 \)
   \( y = -4.5 \)

   
   

   5) \( 2c(c + 6) = 0 \)
   \( 2c = 0 \) или \( c + 6 = 0 \)
   \( c = 0 \) или \( c = -6 \)

   
   

   6) \( \frac{d}{-5.3} = 0.1 \)
   \( d = 0.1 \times (-5.3) \)
   \( d = -0.53 \)

   
   

   7) \( |m| = 4 \)
   \( m = 4 \) или \( m = -4 \)

   
   

   8) \( \frac{2}{-k} = -3 \)
   \( 2 = -3 \times (-k) \)
   \( 2 = 3k \)
   \( k = \frac{2}{3} \)

   
   

Ответ: 1) -1.6; 2) 0.4; 3) 11.5; 4) -4.5; 5) 0 или -6; 6) -0.53; 7) 4 или -4; 8) \(\frac{2}{3}\).