Question

1.( phân tích đa thưc thanh nhân tử) xy.( x+y) + yz.( y+z)+ xz.( x+z) + 2xyz

2. Tính nhanh

3. ( x- 3) . ( x+7) + ( x+4)^2 + 28

Answer 1

Bài 1:

\(xy\left(x+y\right)+yz\left(y+z\right)+xz\left(x+z\right)+2xyz\)

\(=xy\left(x+y\right)+\left[yz\left(y+z\right)+xyz\right]+\left[xz\left(x+z\right)+xyz\right]\)

\(=xy\left(x+y\right)+yz\left(x+y+z\right)+xz\left(x+y+z\right)\)

\(=xy\left(x+y\right)+z\left(x+y+z\right)\left(x+y\right)\)

\(=\left(x+y\right)\left[xy+z\left(x+y+z\right)\right]\)

\(=\left(x+y\right)\left(xy+xz+yz+z^2\right)\)

\(=\left(x+y\right)\left[x\left(y+z\right)+z\left(y+z\right)\right]\)

\(=\left(x+y\right)\left(y+z\right)\left(x+z\right)\)

Answer 2

Bài 2: Đề sai?