20. Решите уравнение: 1) 4(x − 3) = x + 6; 2) 4 − 6(x + 2) = 3 − 5x; 3) (5x + 8) − (8x + 14) = 9; 4) 2,7 + 3y = 9(y − 2,1); 5) 0,3(8 − 3y) = 3,2 − 0,8(y − 7); 6) \(\frac{5}{6}\left(\frac{1}{3}x-\frac{1}{5}\right)=3x+3\frac{1}{3}\).

1. \(4(x-3)=x+6\);
   \(4x-12=x+6\);
   \(3x=18\);
   \(x=6\).
2. \(4-6(x+2)=3-5x\);
   \(4-6x-12=3-5x\);
   \(-8-6x=3-5x\);
   \(-x=11\);
   \(x=-11\).
3. \((5x+8)-(8x+14)=9\);
   \(5x+8-8x-14=9\);
   \(-3x-6=9\);
   \(-3x=15\);
   \(x=-5\).
4. \(2.7+3y=9(y-2.1)\);
   \(2.7+3y=9y-18.9\);
   \(21.6=6y\);
   \(y=3.6\).
5. \(0.3(8-3y)=3.2-0.8(y-7)\);
   \(2.4-0.9y=8.8-0.8y\);
   \(-0.1y=6.4\);
   \(y=-64\).
6. \(\frac{5}{6}\left(\frac{1}{3}x-\frac{1}{5}\right)=3x+3\frac{1}{3}\);
   \(\frac{5}{18}x-\frac{1}{6}=3x+\frac{10}{3}\);
   \(5x-3=54x+60\);
   \(-49x=63\);
   \(x=-\frac{9}{7}\).

Ответ: 1) \(x=6\); 2) \(x=-11\); 3) \(x=-5\); 4) \(y=3.6\); 5) \(y=-64\); 6) \(x=-\frac{9}{7}\).