a)
\(-5+2x=-45\Leftrightarrow2x=-45+5\Leftrightarrow2x=-40\Leftrightarrow x=-20\)
\(-\dfrac{x}{4}=\dfrac{28}{16}\Leftrightarrow-\dfrac{4x}{16}=\dfrac{28}{16}\Leftrightarrow-4x=28\Rightarrow x=-\dfrac{28}{4}=-7\)
-5 + 2x = -45
2x = -45 - (-5)
2x = -40
x = -40 : 2
x = -20
Vậy x = -2