a) x^2+2xy+y^2-16
b) 3x^2+5x-3xy-5y
c) 4x^2-6x^3y-2x^2+8x
d) x^2-4-2xy+y^2
e) x^3-4x^2-12x+27
g) 3x^2-18x+27
h) x^2-y^2-z^2-2yz
k) 4x^2(x-6)+9y^2(6-x)
l)6xy+5x-5y-3x^2-3y^2
phân tích thành nhân tử
b. x^2+2xy+y^2-16
c. 3x^2+5x-3xy-5y
d. 4x^2-6x^3y-2x^2+8x
e. x^2-4-2xy+y^2
k. x^2-y^2-z^2-2yz
m. 6xy+5x-5y-3x^2-3y^2
b)x2+2xy+y2-16=(x+y)2-42=(x+y+4)(x+y-4)
c)3x2+5x-3xy-5y=x(3x+5)-y(3x+5)=(3x+5)(x-y)
d)4x2-6x3y-2x2+8x=2x(2x-3x2y-x+4)
e)x2-4-2xy+y2=(x2-2xy+y2)-4=(x-y)2-22=(x-y-2)(x-y+2)
k)x2-y2-z2-2yz=x2-(y+z)2=(x-y-z)(x+y+z)
m)6xy+5x-5y-3x2-3y2=3(x2-2xy+y2)+5(x-y)=3(x-y)2+5(x-y)=(x-y)(3x-3y+5)
b. (x^2+2xy+y^2)-16 =(x+y)^2-16=(x+y+4)(x+y-4)
Phân tích đa thức thành nhân tử.
a,3x^2-3xy-5x+5y
b,x^2+4x-45
c,3y^3+6xy^2+3x^2y
d,x^3-3x^2-4x+12
e,x^3+3x^2+3x+1
f,x^2-3x+xy-3y
g,x^2-2xy+y^2-4
h,x^2-2xy+y^2-z^2
i,3x^2+6xy+3y^2-3z^2
HUHU. AI GIÚP EM VỚI. EM CẦN NỘP GẤP.
PP nhóm
1)2xy+3z+6y+xz
2)x^4-9x^3+x^2-9x
3)x^2-xy+x-y
4)xz+yz-5(x+y)
5)3x^2-3xy-5x+5y
6)x^2+4x-y^2+4
7)3x^2+6xy+3y^2-3z^2
8)x^2-2xy+y^2-z^2+2zt-t^2
1)2xy+3z+6y+xz
= x(2y + z) + 3(z + 2y)
= (x + 3)(2y + z)
2)x^4-9x^3+x^2-9x
= x^2(x^2 + 1) - 9x(x^2 + 1)
= (x^2 + 1)(x^2 - 9x)
= x(x - 9)(x^2 + 1)
3)x^2-xy+x-y
= x(x - y) + (x - y)
= (x + 1)(x - y)
4)xz+yz-5(x+y)
= z(x + y) - 5(x + y)
= (z - 5)(x + y)
5)3x^2-3xy-5x+5y
= 3x(x - y) - 5(x - y)
= (3x - 5)(x - y)
6)x^2+4x-y^2+4y
= (x - y)(x + y) + 4(x + y)
= (x - y + 4)(x + y)
1/ tìm GTNN
4x^2+y^2-4x-2y+3
X^2+y^2+2*(x-2y)y+6
2 phân tich đa thức thành nhân tử
(x+y)^2-25(x+y)+24
2x^3y-2xy-4xy-2xy
y^2 +3xy+3y^2 (y#0)
(x^2+4x+8)^2-3x(x^2+4x+8) +x^2
x^3-y^3-3x+3y
x^4+6x^2+13x^2+12x+4
Phân tích các đa thức sau thành nhân tử
a) \(^{ }3xy-6xy^2\)
b) \(^{ }3x^3+6x^2+3x\)
c) \(^{ }x^3-x^2+2\)
d) \(^{ }x^2+4x+4-y^2\)
e) \(^{ }x^3+4x^2+4x\)
f) \(^{ }x^2+2x+1-9y^2\)
g) \(^{ }6x^2-12x\)
h) \(^{ }x^3+2x^2-x\)
i) \(^{ }x^2-2xy+y^2-9\)
j) \(^{ }x^2+x-6\)
k) \(^{ }2x^3+2x^2y-4xy^2\)
l) \(^{ }x^3-4x^2-12x+27\)
a) \(3xy-6xy^2=3xy\left(1-2y\right)\)
b) \(3x^3+6x^2+3x=3x\left(x^2+2x+1\right)=3x\left(x+1\right)^2\)
c) \(x^3-x^2+2\)
d) \(x^2+4x+4-y^2=\left(x^2+4x+4\right)-y^2=\left(x+2\right)^2-y^2=\left(x-y+2\right)\left(x+y+2\right)\)
e) \(x^3+4x^2+4x=x\left(x^2+4x+4\right)=x\left(x+2\right)^2\)
f) \(x^2+2x+1-9y^2=\left(x+1\right)^2-\left(3y\right)^2=\left(x-3y+1\right)\left(x+3y+1\right)\)
g) \(6x^2-12x=6x\left(x-2\right)\)
h) \(x^3-2x^2+x=x\left(x^2-2x+1\right)=x\left(x-1\right)^2\)
i) \(x^2-2xy+y^2-9=\left(x-y\right)^2-3^2=\left(x-y-3\right)\left(x-y+3\right)\)
k) \(2x^3+2x^2y-4xy^2=2x\left(x^2+xy-2y^2\right)\)
l) \(x^3-7x^2+9x+3x^2-21x+27=x\left(x^2-7x+9\right)+3\left(x^2-7x+9\right)=\left(x+3\right)\left(x^2-7x+9\right)\)
Tìm x,y,z biết: a) x^2+y^2-4x+4y+8=0 b) 5x^2-4xy+y^2=0 c) x^2+2y^2+z^2-2xy-2y-4z+5=0 d) 3x^2+3y^2+3xy-3x+3y+3=0 e) 2x^2+y^2+2z^2-2xy-2xz+2yz-2z-2z-2x+2=0
a) x2+y2-4x+4y+8=0
⇔ (x-2)2+(y+2)2=0
\(\Leftrightarrow\left\{{}\begin{matrix}x-2=0\\y+2=0\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=2\\y=-2\end{matrix}\right.\)
b)5x2-4xy+y2=0
⇔ x2+(2x-y)2=0
\(\Leftrightarrow\left\{{}\begin{matrix}x=0\\2x-y=0\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=0\\y=0\end{matrix}\right.\)
c)x2+2y2+z2-2xy-2y-4z+5=0
⇔ (x-y)2+(y-1)2+(z-2)2=0
\(\Leftrightarrow\left\{{}\begin{matrix}x-y=0\\y-1=0\\z-2=0\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=y=1\\z=2\end{matrix}\right.\)
b: Ta có: \(5x^2-4xy+y^2=0\)
\(\Leftrightarrow x^2-\dfrac{4}{5}xy+y^2=0\)
\(\Leftrightarrow x^2-2\cdot x\cdot\dfrac{2}{5}y+\dfrac{4}{25}y^2+\dfrac{21}{25}y^2=0\)
\(\Leftrightarrow\left(x-\dfrac{2}{5}y\right)^2+\dfrac{21}{25}y^2=0\)
Dấu '=' xảy ra khi \(\left\{{}\begin{matrix}x=0\\y=0\end{matrix}\right.\)
d)3x2+3y2+3xy-3x+3y+3=0
⇔ 6x2+6y2+6xy-6x+6y+6=0
⇔ 3(x+y)2+3(x-1)2+3(y+1)2=0
\(\Leftrightarrow\left\{{}\begin{matrix}x+y=0\\x-1=0\\y+1=0\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=1\\y=-1\end{matrix}\right.\)
PP nhóm
1)x^2+x-y^2+y
2)4x^2-9y^2+4x-6y
3)x^2+x+y^2+y+2xy
4)-x^2+5x+2xy-5y-y^2
5)x^2-y^2+2x+1
6)x^2-1-y^2+2y
7)x^2+2xz-y^2+2uy+z^2-u^2
8)x^3+3x^2y+x+3xy^2+y+y^3
9)x^3+y(1-3x^2)+x(3y^2-1)-y^3
10)27x^3+27x^2+9x+1+x+1/3
1) x2 + x - y2 + y = (x2 - y2) + (x + y) = (x - y)(x + y) + (x + y) = (x - y + 1)(x + y)
2) 4x2 - 9y2 + 4x - 6y = (4x2 - 9y2) + (4x - 6y) = (2x - 3y)(2x + 3y) + 2(2x - 3y) = (2x - 3y)(2x + 3y + 2)
3) x2 + x + y2 + y + 2xy = (x2 + 2xy + y2) + (x + y) = (x + y)2 + (x + y) = (x + y)(x + y + 1)
4) -x2 + 5x + 2xy - 5y - y2 = -(x2 - 2xy + y2) + (5x - 5y) = -(x - y)2 + 5(x - y) = (x - y)(y - x + 5)
5) x2 - y2 + 2x + 1 = (x2 + 2x + 1) - y2 = (x + 1)2 - y2 = (x + 1 + y)(x - y + 1)
6) x2 - 1 - y2 + 2y = x2 - (y2 - 2y + 1) = x2 - (y - 1)2 = (x - y + 1)(x + y - 1)
7) x2 + 2xz - y2 + 2uy + z2 - u2 =(x2 + 2xz + z2) - (y2 - 2uy + u2) = (x + z)2 - (y - u)2 = (x + z - y + u)(x + z + y - u)
8) x3 + 3x2y + x + 3xy2 + y + y3 = (x3 + 3x2y + 3xy2 + y3) + (x + y) = (x + y)3 + (x + y) = (x + y)(x2 + 2xy + y2 + 1)
9) x3 + y(1 - 3x2) + x(3y2 - 1) - y3 = x3 + y - 3x2y + 3xy2 - x - y3 = (x3 - 3x2y + 3xy2 - y3) - (x - y) = (x - y)3 - (x - y) = (x - y)(x2 - 2xy+y2-1)
Chia đa thức cho đơn thức
a, (8x^4 - 4x^3 +x^2) : 2x^2
b, 2x^4 - x^3 + 3x^2) : (-1/3x^2)
c, (-18x^3y^5 + 12x^2y^2 - 6xy^3) : 6xy
d,(3/4x^3y^6 + 6/5x^4y^5 - 9/10x^5y) : (-3/5x^3y)
giúp mìn với ạ
\(a.\left(8x^4-4x^3+x^2\right):2x^2=4x^2-2x+\frac{1}{2}\)
\(b.\left(2x^4-x^3+3x^2\right):\left(-\frac{1}{3x^2}\right)=-6x^6+3x^5-9x^4\)
\(c.\left(-18x^3y^5+12x^2y^2-6xy^3\right):6xy=-3x^2y^4+2xy-y^2\)
\(d.\left(\frac{3}{4x^3y^6}+\frac{6}{5x^4y^5}-\frac{9}{10x^5y}\right):-\frac{3}{5x^3y}=-\frac{5}{4y^5}-\frac{2}{xy^4}-\frac{3}{2x^2}\)
Phân tích đa thức thành nhân tử
1/x^3 - 2x^2 - 9x + 18 2/3x^2 -5x - 3y^2 + 5y
3/49 - x^2 + 2xy - y^2 4/ 1/2x^2 - 2y^2
5/ x^2 - 4x^2y^2 + 2xy 6/ 3x - 3y - x^2 + 2xy - y^2
1/x^3 - 2x^2 - 9x + 18
= x\(^2\)( x - 2 ) - 9 ( x - 2 ) = ( x\(^2\) - 9 ) ( x - 2 )= ( x - 3 ) ( x +3 ) ( x - 2 )
2/3x^2 -5x - 3y^2 + 5y
= 3( x\(^2\) - y\(^2\) ) - 5 ( x - y ) = 3 ( x - y ) ( x + y ) - 5 ( x - y ) = ( x - y ) [ 3( x+ y ) - 5 ]
= ( x - y ) ( 3x + 3y - 5 )
3/49 - x^2 + 2xy - y^2
= 49 - ( x\(^2\) - 2xy + y\(^2\) ) = 49 - ( x - y )\(^2\) = ( 7 - x + y ) ( 7 + x - y )
5/ x^2 - 4x^2y^2 + 2xy
= x ( x - 4xy\(^2\) + 2y )
6/ 3x - 3y - x^2 + 2xy - y^2
= ( 3x - 3y ) - ( x\(^2\) - 2xy + y\(^2\) ) = 3 ( x - y ) - ( x - y )\(^2\) = ( x - y ) ( 3 - x + y )