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[(x2-2xy+2xy2).(x+2y)-(x2+4y2).(x-y)]2xy
=( x3 + 2x2y-2x2y-4xy2+2x2y2+4xy3-x3+x2y-4xy2+4y3 )2xy
=2xy(2x2y2-8xy2+4xy3+x2y+4y3)
= 4x3y3-16x2y3+8x2y4+2x3y2+8xy4
Trả lời:
[ ( x2 - 2xy + 2xy2 ) ( x + 2y ) - ( x2 + 4y2 ) ( x - y ) ] 2xy
= [ ( x3 + 2x2y - 2x2y - 4xy2 + 2x2y2 + 4xy3 ) - ( x3 - x2y + 4xy2 - 4y3 ) ] 2xy
= ( x3 + 2x2y - 2x2y - 4xy2 + 2x2y2 + 4xy3 - x3 + x2y - 4xy2 + 4y3 ) 2xy
= ( x2y - 8xy2 + 2x2y2 + 4xy3 + 4y3 ) 2xy
= 2x3y2 - 16x2y3 + 4x3y3 + 8x2y4 + 8xy4
Bài 1
a) (6x4y2 - 3x3y3) : 3x3y2 = 6x4y2 : 3x3y2 - 3x3y3 : 3x3y2 = 2x - y
b) (2x - 1)(x2 - x + 3) = 2x3 - 2x2 + 6x - x2 + x - 3 = 2x3 - 3x2 + 7x - 3
Bài 2
1) (x - 2)2 - (x - 3)2 = (x - 2 - x + 3)(x - 2 + x - 3) = 2x - 5>
2) 4x2 - 4xy + 2y2 + 1 = (4x2 - 4xy + y2) + y2 + 1 = (2x - y)2 + y2 + 1 > 0
vì \(\hept{\begin{cases}\left(2x-y\right)^2\ge0\\y^2\ge0\end{cases}}\)
bài 1, bạn tự làm nhé đặt chia đi bạn
bài 2
a,\(\left(x^2-2xy+y^2\right)+2\left(x-y\right)=\left(x-y\right)^2+2\left(x-y\right)=\left(x-y\right)\left(x-y+2\right)\)
\(b,=a^2-2a-5a+10=a\left(a-2\right)-5\left(a-2\right)=\left(a-2\right)\left(a-5\right)\)
1, = [(x-1)^2-y^2] : (x-y-1)
= (x+y-1).(x-y-1) : (x-y-1) = x+y-1
2, x^2-x-y^2+y = (x^2-y^2)-(x-y) = (x-y).(x+y) - (x-y) = (x-y).(x+y+1)
k mk nha
(5x - 2y)(x2 - xy + 1)
= 5x3 - 5x2y + 5x - 2x2y + 2xy2 - 2y
= 5x3 - 7x2y + 2xy2 + 5x - 2y
(x - 1)(x + 1)(x + 2)
= (x2 - 1)(x + 2)
= x3 + 2x2 - x - 2
1/2x2y2(2x + y)(2x - y)
= 1/2x2y2(4x2 - y2)
= 2x4y2 - 1/2x2y4
1.
a) \(\left(-2x^3\right)\)\(\left(x^2+5x-\frac{1}{2}\right)\) = \(-2x^5\)\(-10x^4\) \(+x^3\)
b) (\(6x^3-7x^2\)\(-x+2\))\(:\left(2x+1\right)\)=\(3x^2-5x+2\)
2.
a) 9x(3x-y) + 3y (y-3x)=9x(3x-y)-3y(3x-y)
= (9x-3y)(3x-y)
= 3(3x-y)(3x-y)
= 3(3x-y)^2
b) \(x^3-3x^2\)\(-9x+27\)= \(\left(x^3-3x^2\right)\)\(-\left(9x-27\right)\)
= \(x^2\left(x-3\right)\)\(-9\left(x-3\right)\)
= \(\left(x^2-9\right)\left(x-3\right)\)
= \(\left(x+3\right)\left(x-3\right)\left(x-3\right)\)
= \(\left(x+3\right)\left(x-3\right)^2\)
Bài 1 ) a ) \(\left(-2x^3\right)\left(x^2+5x-\frac{1}{2}\right)\)
\(=-2x^5-10x^4+x^3\)
b ) \(\left(6x^3-7x^2+x+2\right):\left(2x+1\right)\)
\(=3x^2-5x+2\)
2 ) a ) \(9x\left(3x-y\right)+3y\left(y-3x\right)\)
\(=9x\left(3x-y\right)-3y\left(3x-y\right)\)
\(=\left(3x-y\right)\left(9x-3y\right)\)
\(=3\left(3x-y\right)\left(x-y\right)\)
b ) \(x^3-3x^2-9x+27\)
\(=\left(x^3-3x^2\right)-\left(9x-27\right)\)
\(=x^2\left(x-3\right)-9\left(x-3\right)\)
\(=\left(x^2-9\right)\left(x-3\right)\)
\(=\left(x-3\right)\left(x+3\right)\left(x-3\right)\)
a)\(\left(3x^2+2xy\right).\left(5xy^2-4x+\frac{1}{3}y^2\right)\)
\(=15x^3y^2-12x^3+x^2y^3+10x^2y^3-8x^2y+\frac{2}{3}xy^4\)
\(=15x^3y^2-12x^3+11x^2y^3-8x^2y+\frac{2}{3}xy^4\)
b)\(\left(x^3-x^2-7x+3\right):\left(x-3\right)\)
\(=\left(x^3-3x^2+2x^2-6x-x+3\right):\left(x-3\right)\)
\(=\left[x^2\left(x-3\right)+2x\left(x-3\right)-\left(x-3\right)\right]:\left(x-3\right)\)
\(=\left(x-3\right)\left(x^2+2x-1\right):\left(x-3\right)\)
\(=x^2+2x-1\)
- xy - xy - xy = - 1xy - 1xy - 1xy = - 3xy
X3 -XY - X3 - X2Y + X2Y -XY = -2XY