a ) \(4.\left(x-8\right)< 0\)
\(\Leftrightarrow4x-32< 0\)
\(\Leftrightarrow4x< 32\)
\(\Leftrightarrow x< 8\)
b ) \(-3\left(x.2\right)< 0\)
\(\Leftrightarrow-6x< 0\)
\(\Leftrightarrow x>0\)
\(\text{a) }4\left(x-8\right)< 0\)
\(\Leftrightarrow x-8< 0\div4\)
\(\Leftrightarrow x-8< 0\)
\(\Leftrightarrow x< 0+8\)
\(\Leftrightarrow x< 8\)
\(\Rightarrow x\in\left\{...;0;1;2;3;4;5;6;7\right\}\)
\(\text{b) }-3\left(2x\right)< 0\)
\(\Leftrightarrow2x< \frac{0}{-3}\)
\(\Leftrightarrow2x< 0\)
\(\Leftrightarrow x< 0\div2\)
\(\Leftrightarrow x< 0\)
\(\Rightarrow\hept{\begin{cases}x\inℤ\\x\notinℕ^∗\end{cases}}\)
