\(x+x.\frac{1}{4}:\frac{2}{7}+x:\frac{2}{9}=255\)
\(=x+x.\left(\frac{1}{4}:\frac{2}{7}\right)+x:\frac{2}{9}=255\)
\(=x+x.\frac{7}{8}+x:\frac{2}{9}=255\)
\(=x+x.\frac{7}{8}+x.\frac{9}{2}=255\)
\(=x+x.\left(\frac{7}{8}+\frac{9}{2}\right)=255\)
\(=x+x.\frac{43}{8}=255\)
\(\Leftrightarrow x=40\)
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