Bài 2: Tìm x:
1. 71 – (33 + x) = 26
2. (x + 73) – 26 = 76
3. (x + 7) – 25 = 13
4. 198 – (x + 4) = 120
5. 5x + x = 39 – 311:39
6. 0 : x = 0
7. 3x = 9
8. 4x = 64
9. 7x – x = 521 : 519 + 3.22 - 70
10. 7x – 2x = 617: 615 + 44 : 11
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