4x^2-6x = 2x ( 2x - 3 )

4x² - 6x

= 2x . 2x - 2x . 3

= 2x( 2x - 3)

Trả lời :

4x² - 6x

= 2x( 2x - 3 )

4x² - 6x

= 2x . (2x - 3)

x² - 6x - 4x + 24 = 0

( x² - 6x ) - ( 4x - 24 ) = 0

x( x - 6 ) - 4 ( x - 6 ) = 0

( x - 4 ) ( x - 6 ) = 0

\(\Rightarrow\orbr{\begin{cases}x-4=0\Rightarrow x=4\\x-6=0\Rightarrow x=6\end{cases}}\)

Vay x= 4 hoac x = 6

x² - 6x - 4x + 24 = 0

( x² - 6x ) - ( 4x - 24 ) = 0

x ( x - 6 ) - 4 ( x - 6 ) = 0

( x - 4 ) ( x - 6 ) = 0

\(\Rightarrow\orbr{\begin{cases}x-4=0\\x-6=0\end{cases}}\)

1. x - 4 = 0    => x = 4

2. x - 6 = 0    => x = 6

\(6x^2y-4x^3y=2x^2y\left(3-2x\right)\)

\(12x-9-4x^2=-\left(2x-3\right)^2\\ Sửa:x^3-6x^2y+12xy^2-8y^3=\left(x-2y\right)^3\)

a: \(2y\left(x+2\right)-3x-6\)

\(=2y\left(x+2\right)-3\left(x+2\right)\)

\(=\left(x+2\right)\left(2y-3\right)\)

b: \(3\left(x+4\right)-x^2-4x\)

\(=3\left(x+4\right)-\left(x^2+4x\right)\)

\(=3\left(x+4\right)-x\left(x+4\right)\)

\(=\left(x+4\right)\left(3-x\right)\)

c: \(2\left(x+5\right)-x^2-4x\)

\(=2x+10-x^2-4x\)

\(=-x^2-2x+10\)

\(=-x^2-2x-1+11\)

\(=11-\left(x^2+2x+1\right)\)

\(=11-\left(x+1\right)^2\)

\(=\left(\sqrt{11}-x-1\right)\left(\sqrt{11}+x+1\right)\)

d: \(x^2+6x-3x-18\)

\(=\left(x^2+6x\right)-\left(3x+18\right)\)

\(=x\left(x+6\right)-3\left(x+6\right)\)

\(=\left(x+6\right)\left(x-3\right)\)

a)  \(4x^2+20x+25=\left(2x+5\right)^2\)

b) \(x^2-6x+9=\left(x-3\right)^2\)

c) \(4x^2+12x+9=\left(2x+3\right)^2\)