Exomple 2 20. The formula \( a=\frac{h}{b} \) can be used to find the batting average a of a batter who has \( h \) hits in \( b \) times at bat a. Solve the formula for \( b \).

Which of the following equations has no solution? \( \begin{array}{c}5 x+20-7 x=7(3+x)-3 x \\ x+20-5 x=7(3+x)-3 x \\ 5 x+21-x=7(3+x)-3 x \\ 5 x+20-x=7(3+x)-3 x\end{array} \)

a) \( \log _{2} x=1-x \);

a) \( \log _{2} x=1-x \);

6) \( \frac{1}{x-2}=2 \)

Which of the following equations has no solution \( \begin{array}{l}x+20-5 x=7(3+x)-3 x \\ \begin{array}{l}5 x+20-7 x=7(3+x)-3 x \\ 5 x+21-x=7(3+x)-3 x \\ 5 x+20-x=7(3+x)-3 x\end{array} \\ \begin{array}{l}5\end{array}\end{array} \$ \begin{array}{l}\text { - }\end{array} \)