\(A=\dfrac{16x^2-1}{16x^2-8x+1}\)
\(=\dfrac{\left(4x-1\right)\left(4x+1\right)}{\left(4x-1\right)^2}\)
a) ĐKXĐ:
\(\left(4x-1\right)^2\ne0\Leftrightarrow4x-1\ne0\Leftrightarrow x\ne\dfrac{1}{4}\)
b) \(A=\dfrac{\left(4x+1\right)\left(4x-1\right)}{\left(4x-1\right)^2}=\dfrac{4x+1}{4x-1}\)
a,đkxđ : \(16x^2\ne0\Leftrightarrow x\ne0\)
b, \(\dfrac{16x^2}{1}-\dfrac{1}{16x^2}-\dfrac{8x}{1}+1=\dfrac{256x^4}{16x^2}-\dfrac{1}{16x^2}-\dfrac{128x^3}{16x^2}+\dfrac{16x^2}{16x^2}\)
\(=\dfrac{256x^4-1-128x^3+16x^2}{16x^2}=\dfrac{256x^4-128x^3+16x^2-1}{16x^2}\)
\(=\dfrac{\left(256x^4-128x^3+16^2\right)-1}{16x^2}=\dfrac{16x^2\left(16x^2-8x+1\right)-1}{16x^2}\)
\(=\dfrac{\left(4x\right)^2.\left(\left(4x\right)^2-8x+1\right)-1}{16x^2}=\dfrac{\left(4x\right)^2.\left(4x-1\right)^2-1}{16x^2}\)
\(=\dfrac{\left(16x^2-4x\right)^2-1}{16x^2}=\dfrac{\left(16x^2-4x-1\right)\left(16x^2-4x+1\right)}{16x^2}\)
\(=\dfrac{\left(\left(4x\right)^2-4x-1\right)\left(\left(4x\right)^2-4x+1\right)}{\left(4x\right)^2}\)