Đáp án:
\(\begin{array}{l}
a)x > - \dfrac{5}{2}\\
b)x > 2\\
c)\left\{ \begin{array}{l}
x \ne 3\\
x \ge - 1
\end{array} \right.\\
d)x > 2
\end{array}\)
Giải thích các bước giải:
\(\begin{array}{l}
a)DK:2x + 5 > 0\\
\to x > - \dfrac{5}{2}\\
b)DK:\left\{ \begin{array}{l}
x - 2 \ne 0\\
x - 2 \ge 0
\end{array} \right.\\
\to x > 2\\
c)DK:\left\{ \begin{array}{l}
x - 3 \ne 0\\
x + 1 \ge 0
\end{array} \right.\\
\to \left\{ \begin{array}{l}
x \ne 3\\
x \ge - 1
\end{array} \right.\\
d)DK:\left\{ \begin{array}{l}
{x^2} - 4 \ne 0\\
x - 2 \ge 0
\end{array} \right.\\
\to \left\{ \begin{array}{l}
x \ne \pm 2\\
x \ge 2
\end{array} \right.\\
\to x > 2
\end{array}\)
