17/23-(7/21+(11/23-x))=3/23

¹⁷/₂₃-(⁷/₂₁+(¹¹/₂₃-x))=³/₂₃¹⁷/₂₃-⁷/₂₁+¹¹/₂₃-x=³/₂₃-x=³/₂₃-¹⁷/₂₃+⁷/₂₁-¹¹/₂₃-x= -²⁵/₂₃+⁷/₂₁-x= -²⁵ˣ²¹/₄₈₃+⁷ˣ²³/₄₈₃-x= -⁵²⁵/₄₈₃+¹⁶¹/₄₈₃-x= -³⁶⁴/₄₈₃x= ³⁶⁴/₄₈₃х≈0,75