a, \(x^3-2x^2+3x-6=x\left(x^2+3\right)-2\left(x^2+3\right)=\left(x-2\right)\left(x^2+3\right)\)
b, \(x^2+2x+1-4y^2=\left(x+1\right)^2-\left(2y\right)^2=\left(x+1-2y\right)\left(x+1+2y\right)\)
\(\left(-2x\right)\left(3x+1\right)+\left(x-2\right)\left(2x+1\right)=-6x^2-2x+2x^2+x-4x-2\)
\(=-4x^2-5x-2\)
Sửa 2x + 1 => 3x + 1 có vẻ sẽ ok hơn nhé !
a,\(x^3-2x^2+3x-6\)
\(=x^2\left(x-2\right)+3\left(x-2\right)\)
\(=\left(x^2+3\right)\left(x-2\right)\)
b,\(x^2-2x+1-4y^2\)
\(=\left(x-1\right)^2-\left(2y\right)^2\)
\(=\left(x-1-2y\right)\left(x-1+2y\right)\)
b,\(-2x\left(3x+1\right)+\left(x-2\right)\left(2x+1\right)\)
\(=-6x^2-2x+x^2-3x-2\)
\(=-5x^2-5x-2\)
PTĐTTNT
a) x3 - 2x2 + 3x - 6 = x2( x - 2 ) + 3( x - 2 ) = ( x - 2 )( x2 + 3 )
b) x2 - 2x + 1 - 4y2 = ( x2 - 2x + 1 ) - 4y2 = ( x - 1 )2 - ( 2y )2 = ( x - 2y - 1 )( x + 2y - 1 )
Rút gọn biểu thức
( -2x )( 3x + 1 ) + ( x - 2 )( 2x + 1 )
= -6x2 - 2x + 2x2 - 3x - 2
= -4x2 - 5x - 2
c) 2x2(x +1) + 4x(x +1); d) 2 x(y - 1) - 2