200. Решите уравнение: 1) 2x = 18-x; 2) 7x+3=30 - 2x; 3)7-2x=3x-18; 4) 0,2x + 2,7 = 1,4 – 1,1x; 5) 5,4-1,5x = 0,3x - 3,6; 6) 3/8x+15=1/6x+10.

Решение:

1. \( 2x = 18 - x \)
   \( 2x + x = 18 \)
   \( 3x = 18 \)
   \( x = \frac{18}{3} \)
   \( x = 6 \)
2. \( 7x + 3 = 30 - 2x \)
   \( 7x + 2x = 30 - 3 \)
   \( 9x = 27 \)
   \( x = \frac{27}{9} \)
   \( x = 3 \)
3. \( 7 - 2x = 3x - 18 \)
   \( 7 + 18 = 3x + 2x \)
   \( 25 = 5x \)
   \( x = \frac{25}{5} \)
   \( x = 5 \)
4. \( 0,2x + 2,7 = 1,4 - 1,1x \)
   \( 0,2x + 1,1x = 1,4 - 2,7 \)
   \( 1,3x = -1,3 \)
   \( x = \frac{-1,3}{1,3} \)
   \( x = -1 \)
5. \( 5,4 - 1,5x = 0,3x - 3,6 \)
   \( 5,4 + 3,6 = 0,3x + 1,5x \)
   \( 9 = 1,8x \)
   \( x = \frac{9}{1,8} \)
   \( x = 5 \)
6. \( \frac{3}{8}x + 15 = \frac{1}{6}x + 10 \)
   \( 15 - 10 = \frac{1}{6}x - \frac{3}{8}x \)
   \( 5 = (\frac{4}{24} - \frac{9}{24})x \)
   \( 5 = -\frac{5}{24}x \)
   \( x = 5 \cdot (-\frac{24}{5}) \)
   \( x = -24 \)

Ответ: 1) 6; 2) 3; 3) 5; 4) -1; 5) 5; 6) -24.