[tex] \frac{x}{4} - \frac{3}{2} + \frac{21 - 2x}{12} = \frac{13}{6} \\ 3x - 18 + 21 - 2x = 26 \\ x = 23[/tex]

Ответ D) 23

Verified answer

[tex]\displaystyle\bf\\\frac{x}{4} -\frac{3}{2} +\frac{21-2x}{12} =\frac{13}{6} \\\\\\\frac{x}{4} \cdot 12-\frac{3}{2}\cdot 12 +\frac{21-2x}{12} \cdot 12=\frac{13}{6} \cdot 12\\\\\\3x-18+21-2x=26\\\\3x-2x=26+18-21\\\\\boxed{x=23}[/tex]