\[ 2 - \left( \frac{4}{3}p + \frac{1}{7} \right) \times 21 = \frac{17}{4}p - \frac{51}{8} \]
\[ 2 - \left( \frac{4}{3}p \times 21 + \frac{1}{7} \times 21 \right) = \frac{17}{4}p - \frac{51}{8} \]
\[ 2 - \left( 4p \times 7 + 1 \times 3 \right) = \frac{17}{4}p - \frac{51}{8} \]
\[ 2 - (28p + 3) = \frac{17}{4}p - \frac{51}{8} \]
\[ 2 - 28p - 3 = \frac{17}{4}p - \frac{51}{8} \]
\[ -1 - 28p = \frac{17}{4}p - \frac{51}{8} \]
\[ -1 + \frac{51}{8} = \frac{17}{4}p + 28p \]
\[ -\frac{8}{8} + \frac{51}{8} = \left( \frac{17}{4} + \frac{28}{1} \right)p \]
\[ \frac{43}{8} = \left( \frac{17}{4} + \frac{112}{4} \right)p \]
\[ \frac{43}{8} = \frac{129}{4}p \]
\[ p = \frac{43}{8} \div \frac{129}{4} \]
\[ p = \frac{43}{8} \times \frac{4}{129} \]
\[ p = \frac{43 \times 4}{8 \times 129} \]
\[ p = \frac{43}{2 \times 129} \]
\[ p = \frac{43}{258} \]
\[ p = \frac{1}{6} \]
Ответ: 1/6