Question

Answer 1

Bài `3`

\(a,đkxđ:\left\{{}\begin{matrix}x-3\ne0\\x-2\ne0\end{matrix}\right.\\ \Leftrightarrow\left\{{}\begin{matrix}x\ne3\\x\ne2\end{matrix}\right.\)

\(b,A=\dfrac{x^2-4}{\left(x-3\right)\left(x-2\right)}\\ =\dfrac{\left(x-2\right)\left(x+2\right)}{\left(x-3\right)\left(x-2\right)}\\ =\dfrac{x+2}{x-3}\)

Bài `2`

`a,` không rõ .

`b,9x^2-6x+1`

`=(3x)^2 - 2.3x.1+1^2`

`=(3x-1)^2`

`c,x^3-9x+2x^2y+xy^2`

`= x(x^2 -9+ 2xy +y^2)`

`=x[(x^2 +2xy+y^2)-9]`

`=x[(x+y)^2 -3^2]`

`=x(x+y-3)(x+y+3)`