\(=\left(6x^3-x^2-26x+21\right):\left(3-2x\right)\\ =\left(6x^3-9x^2+8x^2-12x-14x+21\right):\left(3-2x\right)\\ =\left(2x-3\right)\left(3x^2+4x-7\right):\left(3-2x\right)\\ =-\left(3x^2+4x-7\right)=-3x^2-4x+7\)

\(1.\) Phân tích đa thức thành nhân tử

\(4-32x^3=-\left(32x^3-4\right)=\left(-4\right)\left(8x^3-1\right)=\left(-4\right)\left(2x-1\right)\left(4x^2+2x+1\right)\)

\(2.\) Thực hiện phép tính

Ta có:  \(-x^2+6x^3-26x+21=6x^3-x^2-26x+21=\left(x-1\right)\left(2x-3\right)\left(3x+7\right)\)

Do đó:

\(\frac{-x^2+6x^3-26x+21}{2x-3}=\frac{\left(x-1\right)\left(2x-3\right)\left(3x+7\right)}{2x-3}=\left(x-1\right)\left(3x+7\right)=3x^2+4x-7\)

a, \(-2x^3y\left(2x^2-3y+5yz\right)=-4x^5y+6x^3y^2-10x^3y^2z\)

b, \(\left(x+3\right)\left(x^2+3x-5\right)=x^3+3x^2-5x+3x^2+9x-15\)

\(=x^3+6x^2+4x-15\)

a) 6x³ + 3x² + 4x + 2

= ( 6x³ + 3x² ) + ( 4x + 2 )

= 3x²( 2x + 1 ) + 2( 2x + 1 )

= ( 2x + 1 )( 3x² + 2 )

=> (  6x³ + 3x² + 4x + 2 ) : ( 3x² + 2 ) = 2x + 1

b) 2x³ - 26x - 24

= 2( x³ - 13x - 12 )

= 2( x³ + 4x² - 4x² + 3x - 16x - 12 )

= 2[ ( x³ + 4x² + 3x ) - ( 4x² + 16x + 12 ) ]

= 2[ x( x² + 4x + 3 ) - 4( x² + 4x + 3 ) ]

= 2( x² + 4x + 3 )( x - 4 )

=> ( 2x³ - 26x - 24 ) : ( x² + 4x + 3 ) = 2( x - 4 ) = 2x - 8

c) x³ - 7x + 6 

= x³ - 3x² + 3x² + 2x - 9x - 6

= ( x³ - 3x² + 2x ) + ( 3x² - 9x + 6 )

= x( x² - 3x + 2 ) + 3( x² - 3x + 2 )

= ( x² - 3x + 2 )( x + 3 )

=> ( x³ - 7x + 6 ) : ( x + 3 ) = x² - 3x + 2

a,\(\left(6x^3+3x^2+4x+2\right)\div\left(3x^2+2\right)\)

\(=\left[3x^2\left(2x+1\right)+2\left(2x+1\right)\right]\div\left(3x^2+2\right)\)

\(=\left[\left(3x^2+2\right)\left(2x+1\right)\right]\div\left(3x^2+2\right)\)

\(=2x+1\)

bài làm sai hết rồi!

toán cái gì mà toán 😡

ng ta hỏi bài chứ có lm bài đâu mà sai

a)\(2x^4-6x^3+x^2+6x-3=0\)

\(\Leftrightarrow2x^4-6x^3+3x^2-2x^2+6x-3=0\)

\(\Leftrightarrow x^2\left(2x^2-6x+3\right)-\left(2x^2-6x+3\right)=0\)

\(\Leftrightarrow\left(x^2-1\right)\left(2x^2-6x+3\right)=0\)

\(\Leftrightarrow\left(x-1\right)\left(x+1\right)\left(2x^2-6x+3\right)=0\)

\(\Leftrightarrow\left[\begin{array}{nghiempt}x-1=0\\x+1=0\\2x^2-6x+3=0\end{array}\right.\)\(\Leftrightarrow\left[\begin{array}{nghiempt}x=1\\x=-1\\\Delta_{2x^2-6x+3}=\left(-6\right)^2-4\left(2.3\right)=12\end{array}\right.\)

\(\Leftrightarrow\left[\begin{array}{nghiempt}x=1\\x=-1\\x_{1,2}=\frac{6\pm\sqrt{12}}{4}\end{array}\right.\)

b)\(x^3+9x^2+26x+24=0\)

\(\Leftrightarrow x^3+5x^2+6x+4x^2+20x+24=0\)

\(\Leftrightarrow x\left(x^2+5x+6\right)+4\left(x^2+5x+6\right)=0\)

\(\Leftrightarrow\left(x^2+5x+6\right)\left(x+4\right)=0\)

\(\Leftrightarrow\left(x+2\right)\left(x+3\right)\left(x+4\right)=0\)

\(\Leftrightarrow\left[\begin{array}{nghiempt}x+2=0\\x+3=0\\x+4=0\end{array}\right.\)\(\Leftrightarrow\left[\begin{array}{nghiempt}x=-2\\x=-3\\x=-4\end{array}\right.\)