Ответ:

  1. \(6x=28-x\); \(7x=28\); \(x=4\).
  2. \(9x-26=30-5x\); \(14x=56\); \(x=4\).
  3. \(7-3x=6x-56\); \(63=9x\); \(x=7\).
  4. \(0.9x-7.4=-0.4x+4.3\); \(1.3x=11.7\); \(x=9\).
  5. \(5.8-1.6x=0.3x-1.8\); \(7.6=1.9x\); \(x=4\).
  6. \(\frac{3}{8}x+19=\frac{7}{12}x+24\); \(-5=\left(\frac{7}{12}-\frac{3}{8}\right)x=\frac{5}{24}x\); \(x=-24\).

Ответ: 1) \(x=4\); 2) \(x=4\); 3) \(x=7\); 4) \(x=9\); 5) \(x=4\); 6) \(x=-24\).