Đáp án:
3) \(m > \dfrac{{64}}{{33}}\)
Giải thích các bước giải:
\(\begin{array}{l}
2)\left\{ \begin{array}{l}
\dfrac{{3x + 8}}{4} > 2x - 5\\
{x^4} - 3x + 2 > {x^4} - 2{x^2} + 1 + 2{x^2}
\end{array} \right.\\
\to \left\{ \begin{array}{l}
\dfrac{{3x + 8 - 8x + 20}}{4} > 0\\
- 3x + 2 > 1
\end{array} \right.\\
\to \left\{ \begin{array}{l}
- 5x + 28 > 0\\
- 3x > - 1
\end{array} \right.\\
\to \left\{ \begin{array}{l}
x < \dfrac{{28}}{5}\\
x < \dfrac{1}{3}
\end{array} \right.\\
\to x < \dfrac{1}{3}\\
Do:x \in Z\\
\to {x_{Max}} = 0\\
3)\left\{ \begin{array}{l}
11x > 21\\
2x < 3m - 2
\end{array} \right.\\
\to \left\{ \begin{array}{l}
x > \dfrac{{21}}{{11}}\\
x < \dfrac{{3m - 2}}{2}
\end{array} \right.\\
Ycbt \to \dfrac{{21}}{{11}} < \dfrac{{3m - 2}}{2}\\
\to \dfrac{{42}}{{22}} < \dfrac{{33m - 22}}{{22}}\\
\to 33m - 22 > 42\\
\to 33m > 64\\
\to m > \dfrac{{64}}{{33}}
\end{array}\)
