\[\frac{a}{b} = 10 \Longrightarrow \frac{b}{a} = \frac{1}{10} = 0,1 \Longrightarrow a =\]
\[= 10b\]
\[\frac{2a - 3b}{b} = \frac{20b - 3b}{b} = \frac{17b}{b} = 17\]