a: DKXĐ: \(x\notin\left\{\dfrac{4}{3};-\dfrac{4}{3}\right\}\)
b: ĐKXĐ: x<>3
c: ĐKXĐ: \(x\notin\left\{0;-\dfrac{3}{2}\right\}\)
d: DKXĐ: \(x\notin\left\{0;1;3\right\}\)
\(a,ĐKXĐ:9x^2-16\ne0\Rightarrow\left(3x-4\right)\left(3x+4\right)\ne0\Rightarrow x\ne\pm\dfrac{4}{3}\)
\(b,ĐKXĐ:x^2-6x+9\ne0\Rightarrow\left(x-3\right)^2\ne0\Rightarrow x-3\ne0\Rightarrow x\ne3\)
\(c,ĐKXĐ:2x^2+3x\ne0\Rightarrow x\left(2x+3\right)\ne0\Rightarrow\left\{{}\begin{matrix}x\ne0\\2x+3\ne0\end{matrix}\right.\Rightarrow\left\{{}\begin{matrix}x\ne0\\x\ne-\dfrac{3}{2}\end{matrix}\right.\)
\(d,ĐKXĐ:x^3-4x^2+3x\ne0\Rightarrow x\left(x^2-4x+3\right)\ne0\Rightarrow x\left(x^2-3x-x+3\right)\ne0\Rightarrow x\left[x\left(x-3\right)-\left(x-3\right)\right]\ne0\Rightarrow x\left(x-1\right)\left(x-3\right)\ne0\Rightarrow\left\{{}\begin{matrix}x\ne0\\x-1\ne0\\x-3\ne0\end{matrix}\right.\Rightarrow\left\{{}\begin{matrix}x\ne0\\x\ne1\\x\ne3\end{matrix}\right.\)
