Phân tích đa thức thành nhân tử
A= x3(x2-7)2-36x.
CMR A chia hết cho 210 với mọi x
Phân tích đa thức thành nhân tử
a) x3-y3+2x2-2y2
b) x3+1-x2-x
a.
\(x^3-y^3+2x^2-2y^2\)
\(=\left(x-y\right)\left(x^2+xy+y^2\right)+\left(x-y\right)\left(2x+2y\right)\)
\(=\left(x-y\right)\left(x^2+xy+y^2+2x+2y\right)\)
b.
\(x^3+1-x^2-x\)
\(=\left(x+1\right)\left(x^2-x+1\right)-x\left(x+1\right)\)
\(=\left(x+1\right)\left(x^2-2x+1\right)\)
\(=\left(x+1\right)\left(x-1\right)^2\)
phân tích đa thức thành nhân tử
a) (x+y)3+(x-y)3
b) x3-y3+2x2-2y2
c) x3+1-x2-x
Đề Bài:
a)Phân tích đa thức thành nhân tử:
x^3(x^2-7)^2-36x
b)Cmr:A=n^3(n^2-7)^2-36n chia hết cho 210 với mọi n thuộc N
Bài 1: phân tích đa thức thành nhân tử
a)x2-y2-2x-2y e)x4-2x3+2x-1
b)x2(x+2y)-x-2y f)x4+x3+2x2+x+1
c)x3-4x2-9x+36 g)x2y+xy2+x2z+y2z+2xyz
d)x4+2x3+2x-1 h)3x3-3y2-2(x-y)2
Làm chi tiết giúp mình với ạ , cảm ơn
e) Ta có: \(x^4-2x^3+2x-1\)
\(=\left(x^4-1\right)-2x\left(x^2-1\right)\)
\(=\left(x^2+1\right)\left(x-1\right)\left(x+1\right)-2x\left(x-1\right)\left(x+1\right)\)
\(=\left(x-1\right)\left(x+1\right)\cdot\left(x^2-2x+1\right)\)
\(=\left(x+1\right)\cdot\left(x-1\right)^3\)
h) Ta có: \(3x^2-3y^2-2\left(x-y\right)^2\)
\(=3\left(x^2-y^2\right)-2\left(x-y\right)^2\)
\(=3\left(x-y\right)\left(x+y\right)-2\left(x-y\right)^2\)
\(=\left(x-y\right)\left(3x+3y-2x+2y\right)\)
\(=\left(x-y\right)\left(x+5y\right)\)
a) Ta có: \(x^2-y^2-2x-2y\)
\(=\left(x-y\right)\left(x+y\right)-2\left(x+y\right)\)
\(=\left(x+y\right)\left(x-y-2\right)\)
b) Ta có: \(x^2\left(x+2y\right)-x-2y\)
\(=\left(x+2y\right)\left(x^2-1\right)\)
\(=\left(x+2y\right)\left(x-1\right)\left(x+1\right)\)
c) Ta có: \(x^3-4x^2-9x+36\)
\(=x^2\left(x-4\right)-9\left(x-4\right)\)
\(=\left(x-4\right)\left(x^2-9\right)\)
\(=\left(x-4\right)\left(x-3\right)\left(x+3\right)\)
d) Ta có: \(x^4+2x^3+2x-1\)
\(=\left(x^2-1\right)\left(x^2+1\right)+2x\left(x^2+1\right)\)
\(=\left(x^2+1\right)\left(x^2+2x-1\right)\)
phân tích đa thức thành nhân tử
a,A=x3+y3+z3-3xyz
b,B=(x+y)3+(y-z)3+(z-x)3
c,C=(x2+x+1) (x2+x+2)-12
d,D=bc(b+c)+ac(c-a)-ab(a+b)
a: =(x+y)^3+z^3-3xy(x+y)-3xyz
\(=\left(x+y+z\right)\left[\left(x+y\right)^2-z\left(x+y\right)+z^2\right]-3xy\left(x+y+z\right)\)
\(=\left(x+y+z\right)\left(x^2+2xy+y^2-xz-yz+z^2-3xy\right)\)
\(=\left(x+y+z\right)\left(x^2+y^2+z^2-xy-xz-yz\right)\)
b: \(=\left(x+y+y-z\right)^3-3\left(x+y\right)\left(y-z\right)\left(x+y+y-z\right)+\left(z-x\right)^3\)
\(=\left(x-z\right)^3+\left(z-x\right)^3-3\left(x+y\right)\left(y-z\right)\left(x-z\right)\)
\(=-3\left(x+y\right)\left(y-z\right)\left(x-z\right)\)
c: \(=\left(x^2+x\right)^2+3\left(x^2+x\right)+2-12\)
\(=\left(x^2+x\right)^2+3\left(x^2+x\right)-10\)
=(x^2+x+5)(x^2+x-2)
=(x^2+x+5)(x+2)(x-1)
d: =b^2c+bc^2+ac^2-a^2c-a^2b-ab^2
=b^2c-b^2a+bc^2-a^2b+ac^2-a^2c
=b^2(c-a)+b(c^2-a^2)+ac(c-a)
=(c-a)(b^2+ac)+b(c-a)(c+a)
=(c-a)(b^2+ac+bc+ba)
=(c-a)[b^2+bc+ac+ab]
=(c-a)[b(b+c)+a(b+c)]
=(c-a)(b+c)(b+a)
Bài 5. Phân tích các đa thức thành nhân tử
a) (x2-4x)2-8(x2-4x)+15 b) (x2+2x)2+9x2+18x+20
c) ( x+1)(x+2)(x+3)(x+4)-24 d) (x-y+5)2-2(x-y+5)+1
Bài 6. Phân tích các đa thức thành nhân tử
a) x2y+x2-y-1 b) (x2+x)2+4(x2+x)-12
c) (6x+5)2(3x+2)(x+1)-6
Bài 1:phân tích đa thức thành nhân tử
a)x2-2x-4y2-4y e)x4+2x3+2x2+2x+1
b)x3+2x2+2x+1 f)x5+x4+x3+x2+x+1
c)x3-4x2+12x-27
d)a6-a4+2a3+2a2
Làm chi tiết giúp mình với ạ, cảm ơn
a) \(x^2-2x-4y^2-4y=\left(x^2-4y^2\right)-\left(2x+4y\right)=\left(x-2y\right)\left(x+2y\right)-2\left(x+2y\right)=\left(x+2y\right)\left(x-2y-2\right)\)
b) \(x^3+2x^2+2x+1=\left(x+1\right)\left(x^2-x+1\right)+2x\left(x+1\right)=\left(x+1\right)\left(x^2-x+1+2x\right)=\left(x+1\right)\left(x^2+x+1\right)\)
c) \(x^3-4x^2+12x-27=x^3-3x^2-x^2+3x+9x-27=x^2\left(x-3\right)-x\left(x-3\right)+9\left(x-3\right)=\left(x-3\right)\left(x^2-x+9\right)\)
d) \(a^6-a^4+2a^3+2a^2=a^2\left(a^4-a^2+2a+2\right)=a^2\left[a^2\left(a-1\right)\left(a+1\right)+2\left(a+1\right)\right]=a^2\left(a+1\right)\left(a^3-a^2+2\right)=a^2\left(a+1\right)\left[a^3+a^2-2a^2+2\right]=a^2\left(a+1\right)\left[a^2\left(a+1\right)-2\left(a-1\right)\left(a+1\right)\right]=a^2\left(a+1\right)^2\left(a^2-2a+2\right)\)
a) Ta có: \(x^2-2x-4y^2-4y\)
\(=\left(x^2-4y^2\right)-\left(2x+4y\right)\)
\(=\left(x-2y\right)\left(x+2y\right)-2\left(x+2y\right)\)
\(=\left(x+2y\right)\left(x-2y-2\right)\)
b) Ta có: \(x^3+2x^2+2x+1\)
\(=\left(x^3+1\right)+2x\left(x+1\right)\)
\(=\left(x+1\right)\left(x^2-x+1\right)+2x\left(x+1\right)\)
\(=\left(x+1\right)\left(x^2+x+1\right)\)
d) Ta có: \(a^6-a^4+2a^3+2a^2\)
\(=a^2\left(a^4-a^2+2a+2\right)\)
\(=a^2\left[a^2\left(a^2-1\right)+\left(2a+2\right)\right]\)
\(=a^2\left[a^2\left(a-1\right)\left(a+1\right)+2\left(a+1\right)\right]\)
\(=a^2\cdot\left(a+1\right)\left(a^3-a+2\right)\)
c) Ta có: \(x^3-4x^2+12x-27\)
\(=\left(x^3-27\right)-\left(4x^2-12x\right)\)
\(=\left(x-3\right)\left(x^2+3x+9\right)-4x\left(x-3\right)\)
\(=\left(x-3\right)\left(x^2-x+9\right)\)
phân tích đa thức thành nhân tử
a)x3+2x2+x
x3+2x2+x
= x ( x\(^2\) + 2x + 1 )
= x ( x + 1 )\(^2\)
phân tích đa thức thành nhân tử
a) (x+y)3-x3-y3
`(x+y)^3-x^3-y^3`
`=(x+y)^3-(x^3+y^3)`
`=(x+y)^3-(x+y)(x^2-xy+y^2)`
`=(x+y)[(x+y)^2-x^2+xy-y^2]`
`=(x+y)(x^2+2xy+y^2-x^2+xy-y^2)`
`=(x+y).3xy`
a) Ta có: \(\left(x+y\right)^3-x^3-y^3\)
\(=x^3-x^3+y^3-y^3+3x^2y+3xy^2\)
\(=3xy\left(x+y\right)\)
(x+y)3−x3−y3(x+y)3-x3-y3
=(x+y)3−(x3+y3)=(x+y)3-(x3+y3)
=(x+y)3−(x+y)(x2−xy+y2)=(x+y)3-(x+y)(x2-xy+y2)
=(x+y)[(x+y)2−x2+xy−y2]=(x+y)[(x+y)2-x2+xy-y2]
=(x+y)(x2+2xy+y2−x2+xy−y2)=(x+y)(x2+2xy+y2-x2+xy-y2)
=(x+y).3xy