1: ĐKXĐ: \(x+3\ne0\)
=>\(x\ne-3\)
2: ĐKXĐ: \(2x-4\ne0\)
=>\(2x\ne4\)
=>\(x\ne2\)
3: ĐKXĐ: \(3x+5\ne0\)
=>\(3x\ne-5\)
=>\(x\ne-\dfrac{5}{3}\)
4: ĐKXĐ: \(x^2-4\ne0\)
=>\(x^2\ne4\)
=>\(x\notin\left\{2;-2\right\}\)
5: ĐKXĐ: \(x^2-1\ne0\)
=>\(x^2\ne1\)
=>\(x\notin\left\{1;-1\right\}\)
6: ĐKXĐ: \(\left(x-1\right)^2\ne0\)
=>\(x-1\ne0\)
=>\(x\ne1\)
7: ĐKXĐ: \(\left(4+x\right)^2\ne0\)
=>\(x+4\ne0\)
=>\(x\ne-4\)
8: ĐKXĐ: \(4x^2-4x+1\ne0\)
=>\(\left(2x-1\right)^2\ne0\)
=>\(2x-1\ne0\)
=>\(2x\ne1\)
=>\(x\ne\dfrac{1}{2}\)
9: ĐKXĐ: \(4x^2-1\ne0\)
=>\(x^2\ne\dfrac{1}{4}\)
=>\(x\notin\left\{\dfrac{1}{2};-\dfrac{1}{2}\right\}\)
10: ĐKXĐ: \(x^2-x+1\ne0\)
=>\(\left(x-\dfrac{1}{2}\right)^2+\dfrac{3}{4}\ne0\)(luôn đúng)
=>\(x\in R\)
