CTHH: Fe\(_3\left(PO_4\right)_2\)

PTK : 3.56 + 16.8 + 31.2

          = 358 đvC

j) \(\dfrac{x^2-4}{9x^2-16}\)

ĐKXĐ: \(9x^2-16\ne0\Leftrightarrow\left(3x+4\right)\left(3x-4\right)\ne0\)

\(\Rightarrow\left\{{}\begin{matrix}x\ne\dfrac{4}{3}\\x\ne-\dfrac{4}{3}\end{matrix}\right.\)

m) \(\dfrac{2x-1}{x^2-4x+3}=\dfrac{2x-1}{\left(x-1\right)\left(x-3\right)}\)

ĐKXĐ: \(\left(x-1\right)\left(x-3\right)\ne0\Rightarrow\left\{{}\begin{matrix}x\ne1\\x\ne3\end{matrix}\right.\)

bài 3:

h)\(\dfrac{2x-1}{x^2-4}\)

ĐKXĐ: \(x^2-4\ne0\Rightarrow\left\{{}\begin{matrix}x\ne2\\x\ne-2\end{matrix}\right.\)

i) \(\dfrac{5}{4x^2-1}\)

ĐKXĐ: \(4x^2-1\ne0\Leftrightarrow\left(2x-1\right)\left(2x+1\right)\ne0\)

\(\Rightarrow\left\{{}\begin{matrix}x\ne\dfrac{1}{2}\\x\ne-\dfrac{1}{2}\end{matrix}\right.\)

m) \(\dfrac{x^3-8}{x^2-4}=\dfrac{\left(x-2\right)\left(x^2+2x+4\right)}{\left(x-2\right)\left(x+2\right)}=\dfrac{x^2+2x+4}{x+2}\)

Vậy đa thức M\(=x^2+2x+4\)

j) \(\dfrac{x^2-2x}{x^2-4}=\dfrac{x\left(x-2\right)}{\left(x+2\right)\left(x-2\right)}=\dfrac{x}{x+2}\)

Vậy đa thức \(K\)\(=x\)