Question

Giải rõ ràng giúp e vs ạ

Answer 1

a) 3x-9xy=3.x-3x.3y

Answer 2

Bài 2: 

a: \(2x^4-8x^2=0\)

\(\Leftrightarrow2x^2\left(x^2-4\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x=0\\x=2\\x=-2\end{matrix}\right.\)

b: Ta có: \(\dfrac{2}{5}x\left(x+10\right)-x-10=0\)

\(\Leftrightarrow\left(x+10\right)\left(\dfrac{2}{5}x-1\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x=-10\\x=\dfrac{5}{2}\end{matrix}\right.\)

Answer 3

bài 1:

a) 3x-9xy

= 3x(1-3y)

b)\(18x^2y^2-9x^3y+36xy^2\) 

= \(9xy\left(2xy-x^2+4y\right)\)

c) \(5y\left(y-x\right)+15x\left(x-y\right)\)

= \(5y\left(y-x\right)-15x\left(y-x\right)\)

= \(\left(y-x\right)\cdot\left(5y-15x\right)\)

= \(\left(y-x\right)\cdot5\left(y-3x\right)\)