$\text{1/}$
$\text{a) $(\dfrac{-1}{2})^{2}$ . $\dfrac{7}{4}$ : ($\dfrac{5}{8}$ - 1$\dfrac{3}{16}$)}$
$\text{= $\dfrac{1}{4}$ . $\dfrac{7}{4}$ : ($\dfrac{10}{16}$ - $\dfrac{19}{16}$)}$
$\text{= $\dfrac{7}{16}$ : $\dfrac{-9}{16}$}$
$\text{= $\dfrac{7}{16}$ . $\dfrac{16}{-9}$}$
$\text{= $\dfrac{-7}{9}$}$
$\text{b) 17$\dfrac{6}{11}$ . $\dfrac{4}{27}$ - 8$\dfrac{6}{11}$ : $\dfrac{27}{4}$ + 350%}$
$\text{= 17$\dfrac{6}{11}$ . $\dfrac{4}{27}$ - 8$\dfrac{6}{11}$ . $\dfrac{4}{27}$ + $\dfrac{7}{2}$}$
$\text{= $\dfrac{4}{27}$(17$\dfrac{6}{11}$ - 8$\dfrac{6}{11}$) + $\dfrac{7}{2}$}$
$\text{= $\dfrac{4}{27}$ . 9 + $\dfrac{7}{2}$}$
$\text{= $\dfrac{4}{3}$ + $\dfrac{7}{2}$}$
$\text{= $\dfrac{29}{6}$}$
$\text{2/ }$
$\text{a) (2$\dfrac{3}{4}$ - 1$\dfrac{4}{5}$)x = 1}$
$\text{=> $\dfrac{19}{20}$ . x = 1}$
$\text{=> x = 1 : $\dfrac{19}{20}$}$
$\text{=> x = $\dfrac{20}{19}$.}$
$\text{b) ($x^{2}$ - 9)(3 - 5x) = 0}$
$\text{=> \(\left[ \begin{array}{l}x^{2} - 9 = 0\\3 - 5x = 0\end{array} \right.\) }$
$\text{=> \(\left[ \begin{array}{l}x^{2} = 9\\5x = 3\end{array} \right.\) }$
$\text{=> \(\left[ \begin{array}{l}x = ± 3\\x = \dfrac{3}{5}\end{array} \right.\) }$
$\text{c) |3x - 1| + 2$\dfrac{3}{4}$ = 3$\dfrac{1}{16}$}$
$\text{=> |3x - 1| + $\dfrac{11}{4}$ = $\dfrac{49}{16}$}$
$\text{=> |3x - 1| = $\dfrac{49}{16}$ - $\dfrac{11}{4}$}$
$\text{=> |3x - 1| = $\dfrac{5}{16}$}$
$\text{=> \(\left[ \begin{array}{l}3x - 1 = \dfrac{5}{16}\\3x - 1 = \dfrac{-5}{16}\end{array} \right.\) }$
$\text{=> \(\left[ \begin{array}{l}3x = \dfrac{21}{16}\\3x = \dfrac{11}{16}\end{array} \right.\) }$
$\text{=>\(\left[ \begin{array}{l}x = \dfrac{7}{16}\\x = \dfrac{11}{48}\end{array} \right.\) }$
