a) x^2+x-y^2+y
b) 3x^2+3y^2-6xy-12
c) 3x+3y-x^2-2xy-y^2
d) x^3-x+3x^2+3xy^2-y+y^3
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.
BÀI 9: TÍNH GIÁ TRỊ BIỂU THỨC
a) 2/3x^2y + 3x^2y + x^2y tại x=3 y=7
b) 1/2xy^2 + 1/3xy^2 + 1/6xy^2 tại x=3/4 y= -1/2
c) 2x^3y^3 + 10x^3y^3 - 20x^3y^3 tại x =1 y= -1
d) 2018xy^2 + 16xy^2 - 2016xy^2 tại x= -2 y= -1/3
a: A=2/3x^2y+4x^2y=14/3x^2y
=14/3*9*7=294
b: B=xy^2(1/2+1/3+1/6)=xy^2=3/4*1/4=3/16
c: C=x^3y^3(2+10-20)=-8x^3y^3
=-8*1^3(-1)^3=8
d: D=xy^2(2018+16-2016)
=18xy^2
=18(-2)*1/9=-4
tính giá trị biểu thức biết
\(\text{B=x^2-5-2xy+5y+y^2+2019 tại x=y+7}\)
\(\text{C=x^3-3x^2+3x^2y+3xy^2+y^3-3y^2-6xy+3x+3y+2019 tại x=101-y}\)
Cho x+y=101. Tính: P(x,y)= x3−3x2+3x2y+3xy2+y3−3y2−6xy+3x+3y
P(x,y) = x^3 - 3x^2 + 3x^2y + 3xy^2 + y^3 - 3y^2 - 6xy + 3x + 3y
= ( x^3 + 3x^2y + 3xy^2 + y^3 ) - ( 3x^2 + 3y^2 + 6xy ) + ( 3x + 3y)
= ( x+ y)^3 - 3 ( x^2 + 2xy + y^2) + 3 ( x+ y)
= ( x+ y)^3 - 3 ( x+ y)^2 + 3(x +y)
Thay x+ y = 101 ta có :
= 101^3 - 3.101^2 + 3.101
= 101 . ( 101^2 - 3.101 + 3 )
= 101 .9901
= 1000001
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
a) x^2+2xy+y^2-16
=(x+y)2-16
=(x+y-4)(x+y+4)
b) 3x^2+5x-3xy-5y
=(3x2-3xy)+(5x-5y)
=3x(x-y)+5(x-y)
=(x-y)(3x+5)
c) 4x^2-6x^3y-2x^2+8x
ko bik hoặc sai đề
d) x^2-4-2xy+y^2
=(x-y)2-4
=(x-y+2)(x-y-2)
e) x^3-4x^2-12x+27
=sai đề
g) 3x^2-18x+27
=3(x2-6x+9)
=3(x-3)2
h) x^2-y^2-z^2-2yz
=x2-(y2+z2+2yx)
=x2-(y+z)2
=(x-y-z)(x+y+z)
k) 4x^2(x-6)+9y^2(6-x)
=4x2(x-6)-9y2(x-6)
=(x-6)(4x2-9y2)
=(x-6)(2x-3y)(2x+3y)
l)6xy+5x-5y-3x^2-3y^2
=(5x-5y)+(-3x2+6xy-3y2)
=5(x-y)-3(x2-2xy+y2)
=5(x-y)-3(x-y)2
=(x-y)(5-3(x-y))
=(x-y)(5-3x+3y)
Bài 1 tính nhanh
a/ 156^2-112.156+56^2
b/ x^2-2xy-4z^2+y^2
Bài 2
a/ x^2-y^2-5x+5y
b/ x^2-4x-12
c/ 3x^2-6xy-48+3y^2
Bài 1:
\(a,=\left(156-56\right)^2=100^2=10000\\ b,=\left(x-y\right)^2-4z^2=\left(x-y-2z\right)\left(x-y+2z\right)\)
Bài 2:
\(a,=\left(x-y\right)\left(x+y\right)-5\left(x-y\right)=\left(x-y\right)\left(x+y-5\right)\\ b,=x^2+2x-6x-12=\left(x+2\right)\left(x-6\right)\\ c,=3\left(x^2-2xy-16+y^2\right)=3\left[\left(x-y\right)^2-16\right]\\ =3\left(x-y-4\right)\left(x-y+4\right)\)
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)
Cho x+y =101 . Tính P = x3 - 3x2 + 3x2y + 3xy2 + y3 - 3y2 -6xy +3x +3y +2012
Bài giải:
\(x^3-3x^2+3x^2y+3xy^2+y ^3-3y^2-6xy+3x+3y+2012\)
\(=\left(x^3+3x^2y+3xy^2+y^3\right)-\left(6xy+3x^2+3y^2\right)+\left(3x+3y\right)+2012\)
\(=\left(x+y\right)^3-3\left(2xy+x^2+y^2\right)+3\left(x+y\right)+2012\)
\(=101^3-3.101^2+3.101+2012\)
\(=101^3-3.101^2+3.101-1+2013\)
\(=100^3+2013=1002013\)
Tự kết luận nha bạn ^^
<=>P=(x3+3x2y+3xy2+y3)+(-3x2-3y2)-6xy+(3x+3y)+2012
<=>P=(x+y)3-3(x2+y2)-6xy+3(x+y)+2012
<=>P=(x+y)3-3(x+y)2+6xy-6xy+3(x+y)+2012
<=>P=(x+y)3-3(x+y)2+3(x+y)+2012
<=>P=1013-3.1012+3.101+2012
=>P=1002013
a)\(x^3-3x^2+1-3x\)
b) \(x^2\text{+4x - 2xy - 4y +}y^2\)
c) \(3x^2-6xy+3y^2-12z^2\)
`a,x^3 - 3x^2 + 1 - 3x`
`=x^3 + 1 - 3x^2 - 3x`
`=(x^3 + 1) - 3x(x+1)`
`=(x+1)(x^2 - x + 1) - 3x(x+1)`
`=(x+1)(x^2 - x + 1 - 3x)`
`=(x+1)(x^2 - 4x + 1)`
`b,x^2 + 4x - 2xy - 4y + y^2`
`=(x^2 -2xy + y^2) + (4x-4y)`
`=(x-y)^2 + 4(x-y)`
`=(x-y)(x-y+4)`
`c,3x^2 -6xy + 3y^2 - 12z^2`
`=3(x^2 -2xy +y^2 - 4z^2)`
`=3[(x-y)^2 - (2z)^2]`
`=3(x-y-2z)(x-y+2z)`
a: =x^3+1-3x^2-3x
=(x+1)(x^2-x+1)-3x(x+1)
=(x+1)(x^2-x+1-3x)
=(x+1)(x^2-4x+1)
b: =x^2-2xy+y^2+4x-4y
=(x-y)^2+4(x-y)
=(x-y)(x-y+4)
c: =3(x^2-2xy+y^2-4z^2)
=3[(x-y)^2-4z^2]
=3(x-y-2z)(x-y+2z)
a: =x^3+1-3x^2-3x
=(x+1)(x^2-x+1)-3x(x+1)
=(x+1)(x^2-x+1-3x)
=(x+1)(x^2-4x+1)
b: =x^2-2xy+y^2+4x-4y
=(x-y)^2+4(x-y)
=(x-y)(x-y+4)
c: =3(x^2-2xy+y^2-4z^2)
=3[(x-y)^2-4z^2]
=3(x-y-2z)(x-y+2z)