1) 7 + 2x > 5 + x; 2x - x > 5 - 7; x > -2
3x + 2 < 8 + x; 3x - x < 8 - 2; 2x < 6; x < 3
(-2 < x < 3)
2) 1 - 0.5x < 4 - x; x - 0.5x < 4 - 1; 0.5x < 3; x < 6
9 - 2.8x > 6 - 1.3x; 2.8x - 1.3x < 9 - 6; 1.5x < 3; x < 2
(x < 2)
3) 0.4x - 1 < 0.5x - 1.7; 0.5x - 0.4x > 1.7 - 1; 0.1x > 0.7; x > 7
2.7x - 10 < 0.9x - 1; 2.7x - 0.9 < 10 - 1; 1.8x < 9; x < 5
(x < 5; x > 7)
4) 2.8x - 17 >= 0.3x - 4.5; 2.8x - 0.3x >= 17 - 4.5; 2.5x >= 12.5; x >= 5;
12.3x - 16.6 <= 7.1x + 19.8; 12.3x - 7.1x <= 19.8 + 16.6; 5.2x <= 36.4; x <= 7;</p>
[5 <= x <= 7]</p>