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)=>\(x\in R\)Câu trả lời: 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)=>\(x\in R\)