Ответ:

  1. \((128+49)-x=28\); \(177-x=28\); \(x=149\).
  2. \(x-(133+75)=32\); \(x-208=32\); \(x=240\).
  3. \(145-(x+45)=50\); \(x+45=95\); \(x=50\).
  4. \((39+x)-27=22\); \(39+x=49\); \(x=10\).
  5. \(500-(120-x)=479.99\); \(380+x=479.99\); \(x=99.99\).
  6. \(220+(x-120)=997-736\); \(100+x=261\); \(x=161\).
  7. \(472-(z-444)=302\); \(z-444=170\); \(z=614\).
  8. \(6x+131=437\); \(6x=306\); \(x=51\).
  9. \(490-7y=350\); \(7y=140\); \(y=20\).
  10. \(\frac{k}{16}-109=231\); \(\frac{k}{16}=340\); \(k=5440\).