Hằng đẳng thức mà tương ạ! :v
a, \(\dfrac{8x^3-\dfrac{1}{125}y^3}{4x^2+\dfrac{1}{25}y^2+\dfrac{2}{5}xy}\)
\(=\dfrac{\left(2x-\dfrac{1}{5}y\right)\left(4x^2+\dfrac{2}{5}xy+\dfrac{1}{25}y^2\right)}{4x^2+\dfrac{1}{25}y^2+\dfrac{2}{5}xy}=2x-\dfrac{1}{5}y\)
b, \(\dfrac{x^3-6x^2+2x+15}{x-5}\)
\(=\dfrac{x^3-5x^2-x^2+5x-3x+15}{x-5}\)
\(=\dfrac{x^2\left(x-5\right)-x\left(x-5\right)-3\left(x-5\right)}{x-5}\)
\(=\dfrac{\left(x-5\right)\left(x^2-x-3\right)}{\left(x-5\right)}=x^2-x-3\)
Rồi ạ :v!
đề bài là rút gọn biểu thức à??????
à bạn kia làm rồi hihi nãy chưa nhìn thấy
a)
\(\left(8x^3-\dfrac{1}{125}y^3\right):\left(4x^2+\dfrac{1}{25}y^2+\dfrac{2}{5}xy\right)\)
=\(\left(2x-\dfrac{1}{5}y\right)\left(4x^2+\dfrac{2}{5}xy+\dfrac{1}{25}y^2\right):\left(4x^2+\dfrac{2}{5}xy+\dfrac{1}{25}y^2\right)\)
=\(2x-\dfrac{1}{5}y\)
b)
\(x^3-6x^2+2x+15:\left(x-5\right)\)
=\(x^3-5x^2-x^2+5x-3x+15:\left(x-5\right)\)
=\(x^2\left(x-5\right)-x\left(x-5\right)-3\left(x-5\right)\)
=\(\left(x-5\right)\left(x^2-x+3\right):\left(x-5\right)=x^2-x+3\)
Anh hiếu làm ròi em ko làm nữa :D