[tex]\it \dfrac{\overline{x8} +\overline{x0}}{\overline{8x}+\overline{x9}} =\dfrac{3}{4} \Rightarrow \dfrac{10x+8+10x}{80+x+10x+9} =\dfrac{3}{4} \Rightarrow \dfrac{20x+8}{11x+89} =\dfrac{3}{4} \Rightarrow
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\Rightarrow 4\cdot(20x+8) = 3\cdot(11x+89) \Rightarrow 80x+32 = 33x +267 \Rightarrow
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80x-33x = 267-32 \Rightarrow 47x = 235 \Rightarrow x = 5[/tex]
