Ответ:

  1. Раскроем скобки и перенесём слагаемые: −55x + 154 = −81x + 63; 26x = −91; x = −3.5.

  2. −90x + 180 = 45x + 18; −135x = −162; x = 1.2.

  3. 80x + 90 = −30x + 24; 110x = −66; x = −0.6.

  4. −35x + 35 = 45x − 42; −80x = −77; x = 77/80.

  5. −27x − 99 = −42x + 12; 15x = 111; x = 7.4.

  6. 33x + 33 = 48x − 120; 153 = 15x; x = 10.2.

  7. −28x − 6 = −30x − 21; 2x = −15; x = −7.5.

  8. 48x + 56 = 28x − 2; 20x = −58; x = −2.9.

  9. −40x + 40 = −140x − 20; 100x = −60; x = −0.6.

  10. −14x + 70 = −44x − 143; 30x = −213; x = −7.1.

  11. 54x + 81 = 99x + 126; −45x = 45; x = −1.

  12. −30x + 70 = −25x + 5; −5x = −65; x = 13.

Ответ: 1) −3.5; 2) 1.2; 3) −0.6; 4) 77/80; 5) 7.4; 6) 10.2; 7) −7.5; 8) −2.9; 9) −0.6; 10) −7.1; 11) −1; 12) 13.