一元一次解方程30道题

一元一次方程的标准形式是 ax + b = 0，其中 a 和 b 是常数，x 是未知数。下面是30个一元一次方程的例子及其解法：

1. 2x + 5 = 0

解：x = -5/2

2. 3x 9 = 0

解：x = 3

3. 4x + 12 = 0

解：x = -3

4. 5x 20 = 0

解：x = 4

5. 6x + 18 = 0

解：x = -3

6. 7x 21 = 0

解：x = 3

7. 8x + 24 = 0

解：x = -3

8. 9x 27 = 0

解：x = 3

9. 10x + 30 = 0

解：x = -3

10. 11x 33 = 0

解：x = 3

11. 12x + 36 = 0

解：x = -3

12. 13x 39 = 0

解：x = 3

13. 14x + 42 = 0

解：x = -3

14. 15x 45 = 0

解：x = 3

15. 16x + 48 = 0

解：x = -3

16. 17x 51 = 0

解：x = 3

17. 18x + 54 = 0

解：x = -3

18. 19x 57 = 0

解：x = 3

19. 20x + 60 = 0

解：x = -3

20. 21x 63 = 0

解：x = 3

21. 22x + 66 = 0

解：x = -3

22. 23x 69 = 0

解：x = 3

23. 24x + 72 = 0

解：x = -3

24. 25x 75 = 0

解：x = 3

25. 26x + 78 = 0

解：x = -3

26. 27x 81 = 0

解：x = 3

27. 28x + 84 = 0

解：x = -3

28. 29x 87 = 0

解：x = 3

29. 30x + 90 = 0

解：x = -3

30. 31x 93 = 0

解：x = 3

请注意，上述方程的解都是通过将方程转换为 x = -b/a 的形式来得到的。每个方程都遵循这个解法，只是系数和常数项有所不同。