Ответ: x = 3/5
21. x - 2(3x + 2) = 16 x - 6x - 4 = 16 -5x = 20 x = -4Ответ: x = -4
22. 7x - 15 = 4x - 3(x - 3) 7x - 15 = 4x - 3x + 9 7x - 15 = x + 9 6x = 24 x = 4Ответ: x = 4
23. (4x - 6) - (9x - 4) = 18 4x - 6 - 9x + 4 = 18 -5x - 2 = 18 -5x = 20 x = -4Ответ: x = -4
24. x - 5(x + 3) = 5 x - 5x - 15 = 5 -4x = 20 x = -5Ответ: x = -5
25. 3(5x + 8) - 7x = 6x 15x + 24 - 7x = 6x 8x + 24 = 6x 2x = -24 x = -12Ответ: x = -12
26. 6x - 8 = 5x - 3(x - 4) 6x - 8 = 5x - 3x + 12 6x - 8 = 2x + 12 4x = 20 x = 5Ответ: x = 5
27. 2(4x - 5) - 14 - 3x = 6 8x - 10 - 14 - 3x = 6 5x - 24 = 6 5x = 30 x = 6Ответ: x = 6
28. 5(x - 4.4) = 9x 5x - 22 = 9x -4x = 22 x = -5.5Ответ: x = -5.5
29. 1 - 4(5 + 2x) = 13 1 - 20 - 8x = 13 -19 - 8x = 13 -8x = 32 x = -4Ответ: x = -4
30. 10 - 5(2x - 1) = 7 10 - 10x + 5 = 7 15 - 10x = 7 -10x = -8 x = 4/5 = 0.8Ответ: x = 0.8
31. 5 + 2x = 3(2x - 5) - 8 5 + 2x = 6x - 15 - 8 5 + 2x = 6x - 23 -4x = -28 x = 7Ответ: x = 7
32. 5(x - 3.6) = 9x 5x - 18 = 9x -4x = 18 x = -4.5Ответ: x = -4.5
33. 5(x - 2.4) = 13x 5x - 12 = 13x -8x = 12 x = -1.5Ответ: x = -1.5
34. 16 + 6x = 5(1 - 2x) - 13 16 + 6x = 5 - 10x - 13 16 + 6x = -8 - 10x 16x = -24 x = -1.5Ответ: x = -1.5
35. 2(7x + 11) - 5x = 5x 14x + 22 - 5x = 5x 9x + 22 = 5x 4x = -22 x = -5.5Ответ: x = -5.5
36. 2x - 3(x - 3) = 12 2x - 3x + 9 = 12 -x = 3 x = -3Ответ: x = -3
37. 18 - 5(9 - x) = 8 18 - 45 + 5x = 8 -27 + 5x = 8 5x = 35 x = 7Ответ: x = 7
38. -x = 4 - 3(3x - 8) -x = 4 - 9x + 24 -x = 28 - 9x 8x = 28 x = 3.5Ответ: x = 3.5