Đáp án:
c) \(TXD:D = R\backslash \left\{ { - 2;2} \right\}\)
Giải thích các bước giải:
\(\begin{array}{l}
a)DK:{x^2} - 7x + 12 \ne 0\\
\to x \ne \left\{ {3;4} \right\}\\
\to TXD:D = R\backslash \left\{ {3;4} \right\}\\
b)DK:{x^2} - 2x \ne 0\\
\to x\left( {x - 2} \right) \ne 0\\
\to x \ne \left\{ {0;2} \right\}\\
\to TXD:D = R\backslash \left\{ {0;2} \right\}\\
c)DK:3{x^2} - 12 \ne 0 \to x \ne \left\{ { - 2;2} \right\}\\
\to TXD:D = R\backslash \left\{ { - 2;2} \right\}
\end{array}\)
