2xY+4xY+6xY=...........+10xY=45
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\(1,=\left(x-2\right)\left(5-y\right)\\ 2,=2\left(x-y\right)^2-z\left(x-y\right)=\left(x-y\right)\left(2x-2y-z\right)\\ 3,=5xy\left(x-2y\right)\\ 4,=3\left(x^2-2xy+y^2-4z^2\right)=3\left[\left(x-y\right)^2-4z^2\right]\\ =3\left(x-y-2z\right)\left(x-y+2z\right)\\ 5,=\left(x+2y\right)^2-16=\left(x+2y-4\right)\left(x+2y+4\right)\\ 6,=-\left(6x^2-3x-4x+2\right)=-\left(2x-1\right)\left(3x-2\right)\\ 7,=\left(2x+y\right)\left(2x+y+x\right)=\left(2x+y\right)\left(3x+y\right)\\ 8,=\left(x-y\right)\left(x+5\right)\\ 9,=\left(x+1\right)^2-y^2=\left(x-y+1\right)\left(x+y+1\right)\\ 10,=\left(x^2-9\right)x=x\left(x-3\right)\left(x+3\right)\\ 11,=\left(x-2\right)\left(y+1\right)\\ 12,=\left(x-3\right)\left(x^2-4\right)=\left(x-3\right)\left(x-2\right)\left(x+2\right)\\ 13,=3\left(x+y\right)-\left(x+y\right)^2=\left(x+y\right)\left(3-x-y\right)\)
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\(5x^2-10xy+5y^2-20z^2=5\left(x^2-2xy+y^2-4z^2\right)=5.\left[\left(x-y\right)^2-\left(2z\right)^2\right]=5.\left(x-y-2z\right).\left(x-y+2z\right)\)
\(x^2-z^2+y^2-2xy=\left(x-y\right)^2-z^2=\left(x-y+z\right)\left(x-y-z\right)\)
\(x^2-2xy-4z^2+y^2=\left(x-y\right)^2-4z^2=\left(x-y-2z\right)\left(x-y+2z\right)\)
a) 5x2 - 10xy + 5y2
= 5 (x2 - 2xy + y2)
= 5 (x - y)2
b) x2 - z2 + y2 - 2xy
= (x2 + y2 - 2xy) - z2
= (x2 - 2xy + y2) - z2
= (x - y)2 - z2
= (x - y + z)(x - y - z)
c) x2 - 6xy - 25z2 : hinh nhu de bi sai , ban xem lai giup minh
d) x2 - 2xy - 4z2 + y2
= (x2 - 2xy + y2) - 4z2
= (x - y)2 - (2z)2
= (x - y + 2z)(x - y - 2z)
Chuc ban hoc tot
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a) (2xy+5)(4x^2+5): = 2xy * 4x^2 + 2xy * 5 + 5 * 4x^2 + 5 * 5 = 8x^3y + 10xy + 20x^2 + 25 b) (6xy+4)(2x^2+1): = 6xy * 2x^2 + 6xy * 1 + 4 * 2x^2 + 4 * 1 = 12x^3y + 6xy + 8x^2 + 4 c) (9x^2+4)(3x+5): = 9x^2 * 3x + 9x^2 * 5 + 4 * 3x + 4 * 5 = 27x^3 + 45x^2 + 12x + 20 d) (-2xy+6)(1/2xy+7): = -2xy * 1/2xy + (-2xy) * 7 + 6 * 1/2xy + 6 * 7 = -xy + (-14xy) + 3 + 42 = -15xy + 45 e) (4x+1)(2x^2+5x+2): = 4x * 2x^2 + 4x * 5x + 4x * 2 + 1 * 2x^2 + 1 * 5x + 1 * 2 = 8x^3 + 20x^2 + 8x + 2x^2 + 5x + 2 = 8x^3 + 22x^2 + 13x + 2 f) (2x^2y+3x)(2x+1): = 2x^2y * 2x + 2x^2y * 1 + 3x * 2x + 3x * 1 = 4x^3y + 2x^2y + 6x^2 + 3x g) (4xy+5x^2y)(2xy+6): = 4xy * 2xy + 4xy * 6 + 5x^2y * 2xy + 5x^2y * 6 = 8x^2y^2 + 24xy + 10x^3y + 30x^2y = 8x^2y^2 + 30x^2y + 24xy h) (-1/2x^2+6)(4xy+5): = -1/2x^2 * 4xy + (-1/2x^2) * 5 + 6 * 4xy + 6 * 5 = -2xy + (-5/2x^2) + 24xy + 30 = 22xy + (-5/2x^2) + 30
![](https://rs.olm.vn/images/avt/0.png?1311)
a) 4x2 - 5xy + y2 = 4x2 - 4xy - xy + y2 = 4x( x - y ) - y( x - y ) = ( x - y )( 4x - y )
b) x2 - 4xy + 3y2 = x2 - xy - 3xy + 3y2 = x( x - y ) - 3y( x - y ) = ( x - y )( x - 3y )
c) 9x2 + 6xy - 8y2 = 9x2 - 6xy + 12xy - 8y2 = 9x( x - 2/3y ) + 12y( x - 2/3y ) = ( x - 2/3y )( 9x + 12y )
d) 2x2 + 3xy - 5y2 = 2x2 - 2xy + 5xy - 5y2 = 2x( x - y ) + 5y( x - y ) = ( x - y )( 2x + 5y )
e) x2 - 35y2 - 2xy = x2 + 5xy - 7xy - 35y2 = x( x + 5y ) - 7y( x + 5y ) = ( x + 5y )( x - 7y )
f) 2x2 + 10xy + 8y2 = 2( x2 + 5xy + 4y2 ) = 2( x2 + xy + 4xy + 4y2 ) = 2[ x( x + y ) + 4y( x + y ) ] = 2( x + y )( x + 4y )
g) x2 - 10xy + 16y2 = x2 - 2xy - 8xy + 16y2 = x( x - 2y ) - 8y( x - 2y ) = ( x - 2y )( x - 8y )
h) 4x2 + 4xy - 15y2 = 4x2 - 6xy + 10xy - 15y2 = 4x( x - 3/2y ) + 10y( x - 2/3y ) = ( x - 2/3y )( 4x + 10y )
i) -7xy + 3x2 + 2y2 = 3x2 - xy - 6xy + 2y2 = 3x( x - 1/3y ) - 6y( x - 1/3y ) = ( x - 1/3y )( 3x - 6y )
j) 56y2 + 4x2 - 36xy = 4( x2 - 9xy + 14y2 ) = 4( x2 - 2xy - 7xy + 14y2 ) = 4[ x( x - 2y ) - 7y( x - 2y ) ] = 4( x - 2y )( x - 7y )
![](https://rs.olm.vn/images/avt/0.png?1311)
a) <M = -4x^2 + 6xy - y^2 - (5x^2 - 2xy)
= -4x^2 + 6xy - y^2 - 5x^2 + 2xy
= -9x^2 +8xy - y^2
b) M = (24xy^2 - 13x^2y -+2x^3 ) - (10xy^2 + 2x^2 + 3 )
= 24xy^2 - 13x^2y + 2x^3 - 10xy^2 - 2x^2 - 3
= 14xy^2 - 13x^2y + 2x^3 - 2x^2-3
![](https://rs.olm.vn/images/avt/0.png?1311)
a,
$xy^2+x^2y+(-2xy^2)=xy^2-2xy^2+x^2y=-xy^2+x^2y$
b,
$12x^2y^3z^4+(-7x^2y^3z^4)=12x^2y^3z^4-7x^2y^3z^4=5x^2y^3z^4$
c,
$-6xy^3-(-6xy^3)+6x^3=-6xy^3+6xy^3+6x^3=0+6x^3=6x^3$
d,
$\frac{-x^2}{2}+\frac{7}{2}x^2+x=(\frac{7}{2}-\frac{1}{2})x^2+x$
$=3x^2+x$
e,
$2x^3+3x^3-\frac{1}{3}x^3=(2+3-\frac{1}{3})x^3=\frac{14}{3}x^3$
f,
$5xy^2+\frac{1}{2}xy^2+\frac{1}{4}xy^2=(5+\frac{1}{2}+\frac{1}{4})xy^2$
$=\frac{23}{4}xy^2$
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(2+4+6+....+10)xY=45
[(2+10)x5:2]xY=45
30xY=45
Y=45:30
Y=1,5