Помогите с уравнением 64/70-x+26/70=5/70

64/70 - х + 26/70 = 5/70
64/70 - х = 5/70 - 26/70
64/70 - х = - 21/70
х = 64/70 - (- 21/70)
х = 85/70
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64/70 - 85/70 + 26/70 = 5/70
- 21/70 + 26/70 = 5/70
5/70 = 5/70