a) $\frac{a}{b}$ × 4 + $\frac{1}{6}$ = $\frac{17}{6}$
$\frac{a}{b}$ × 4 = $\frac{17}{6}$ - $\frac{1}{6}$
$\frac{a}{b}$ × 4 = $\frac{16}{6}$ = $\frac{8}{3}$
$\frac{a}{b}$ = $\frac{8}{3}$ ÷ 4
$\frac{a}{b}$ = $\frac{2}{3}$
b) $\frac{4}{5}$ ÷ $\frac{a}{b}$ × 2 = $\frac{16}{5}$
$\frac{4}{5}$ ÷ $\frac{a}{b}$ = $\frac{16}{5}$ ÷ 2
$\frac{4}{5}$ ÷ $\frac{a}{b}$ = $\frac{8}{5}$
$\frac{a}{b}$ = $\frac{4}{5}$ ÷ $\frac{8}{5}$
$\frac{a}{b}$ = $\frac{1}{2}$
