$\text{2/}$
$\text{a) 7 - x = -5}$
$\text{=> x = 7 - (-5)}$
$\text{=> x = 12.}$
$\text{b) 2x - 7 = -19}$
$\text{=> 2x = -19 + 7}$
$\text{=> 2x = -12}$
$\text{=> x = -12 : 2}$
$\text{=> x = -6.}$
$\text{c) |x - 1| + (-5) = 7}$
$\text{=> |x - 1| = 7 - (-5)}$
$\text{=> |x - 1| = 12}$
$\text{=> \(\left[ \begin{array}{l}x - 1 = 12\\x - 1 = -12\end{array} \right.\) }$
$\text{=> \(\left[ \begin{array}{l}x = 12 + 1\\x = -12 + 1\end{array} \right.\) }$
$\text{=> \(\left[ \begin{array}{l}x = 13\\x = -11\end{array} \right.\) }$
$\text{d) 35 - |x + 2| = -9}$
$\text{=> |x + 2| = 35 - (-9)}$
$\text{=> |x + 2| = 44}$
$\text{=> \(\left[ \begin{array}{l}x + 2 = 44\\x + 2 = -44\end{array} \right.\)}$
$\text{=> \(\left[ \begin{array}{l}x = 44 - 2\\x = -44 - 2\end{array} \right.\)}$
$\text{=> \(\left[ \begin{array}{l}x = 42\\x = -46\end{array} \right.\)}$
$\text{3/}$
$\text{a) 35 - (-9 - 13)}$
$\text{= 35 - (-22)}$
$\text{= 57.}$
$\text{b) 82 - [29 + (82 - 29)]}$
$\text{= 82 - [29 - 29 + 82]}$
$\text{= 82 - 82}$
$\text{= 0.}$
$\text{c) (29 - 513) - (487 - 71)}$
$\text{= 29 - 513 - 487 + 71}$
$\text{= (29 + 71) - (513 + 487)}$
$\text{= 100 - 1000}$
$\text{= -900.}$
$\text{d) -419 + (-205 + 419)}$
$\text{= -419 - 205 + 419}$
$\text{= (419 - 419) - 205}$
$\text{= 0 - 205}$
$\text{= -205.}$
