Phân tích đa thức thành nhân tử :
a) \(x^2-2x-9y^2-18y^2\)
b)\(x^2-4x-9y^2+4\)
c)\(x^2-2x-4x^2+1\)
d)\(4x^2-6x-9y^2+9y\)
Phân tích đa thức thành nhân tử A. 4x^2-12xy+9y^2-8x+12y B. 3x^2+20x-7 C. (3x-1)^4+2(9y^2-6x+1)+1 D. 2x^3-3x^2+2x-1
a: =(2x-3y)^2-4(2x-3y)
=(2x-3y)(2x-3y-4)
b: =3x^2+21x-x-7
=(x+7)(3x-1)
c: =(3x-1)^4+2(3x-1)^2+1
=[(3x-1)^2+1]^2
d: =2x^3-2x^2-x^2+x+x-1
=(x-1)(2x^2-x+1)
Phân tích đa thức thành nhân tử
a) (4x^2 - 3x - 18)^2 - (4x^2 + 3x)^2
b) 9(x + y - 1)^2 - 4(2x + 3y +1)^2
c) -4x^2 + 12xy - 9y^2 + 25
d) x^2 - 2xy + y^2 - 4m^2 + 4mn - n^2
a) Ta có: \(\left(4x^2-3x-18\right)^2-\left(4x^2+3x\right)^2\)
\(=\left(4x^2-3x-18-4x^2-3x\right)\left(4x^2-3x-18+4x^2+3x\right)\)
\(=\left(-6x-18\right)\left(8x^2-18\right)\)
\(=-6\left(x+3\right)\cdot2\left(4x^2-9\right)\)
\(=-12\left(x+3\right)\left(2x-3\right)\left(2x+3\right)\)
b) Ta có: \(9\left(x+y-1\right)^2-4\left(2x+3y+1\right)^2\)
\(=\left(3x+3y-3\right)^2-\left(4x+6y+2\right)^2\)
\(=\left(3x+3y-3-4x-6y-2\right)\left(3x+3y-3+4x+6y+2\right)\)
\(=-\left(x+3y+5\right)\left(7x+9y-1\right)\)
c) Ta có: \(-4x^2+12xy-9y^2+25\)
\(=-\left(4x^2-12xy+9y^2-25\right)\)
\(=-\left[\left(2x-3y\right)^2-25\right]\)
\(=-\left(2x-3y-5\right)\left(2x-3y+5\right)\)
d) Ta có: \(x^2-2xy+y^2-4m^2+4mn-n^2\)
\(=\left(x^2-2xy+y^2\right)-\left(4m^2-4mn+n^2\right)\)
\(=\left(x-y\right)^2-\left(2m-n\right)^2\)
\(=\left(x-y-2m+n\right)\left(x-y+2m-n\right)\)
a) (4x2-3x-18)2-(4x2+3x)2
=(4x2-3x-18-4x2-3x)(4x2-3x-18+4x2+3x)
=(-6x-18)(8x2-18)
=-48x3+108x-144x2+324
Phân tích đa thức thành nhân tử
1)4x^2+2x-36x-9y+81y^2
2)x^4-5x^2+4
2) \(x^4-5x^2+4\)
\(=x^4-x^2-4x^2+4\)
\(=x^2\left(x^2-1\right)-4\left(x^2-1\right)\)
\(=\left(x^2-1\right)\left(x^2-4\right)\)
\(=\left(x-1\right)\left(x+1\right)\left(x-2\right)\left(x+2\right)\)
Phân tích đa thức sau thành nhân tử: a) x^2-4x+4-y^2 b) x^2+6x-4y^2+9 c) x^2-6xy+9y^2-36
a) = (x - 2)2 - y2
= (x - 2 - y)(x + 2 + y)
b) = (x^2 + 6x + 9) - (2y)^2
= (x + 3)2 - (2y)2
= (x - 2y + 3)(x + 2y + 3)
c) = (x - 3y)2 - 62
= (x - 3y - 6)(x - 3y + 6)
Phân tích các đa thức sau thành nhân tử
a) 4x2-9y2+6x-9y
b) 1-2x+2yz+x2-y2-z2
c) x3-1+5x2-5+3x-3
a)
\(4x^2-9y^2+6x-9y=\left(2x-3y\right)\left(2x+3\right)+3\left(2x-3y\right)\)
\(=\left(2x-3y\right)\left(2x+3y+3\right)\)
b)
\(1-2x+2yz+x^2-y^2-z^2=\left(x^2-2x+1\right)-\left(y^2-2yz+z^2\right)\) (đổi dấu)
\(=\left(x-1\right)^2-\left(y-z\right)^2\)
c)
\(x^3-1+5x^2-5+3x-3=\left(x-1\right)\left(x^2+x+1\right)+5\left(x-1\right)\left(x+1\right)+3\left(x-1\right)\)
\(=\left(x-1\right)\left(x^2+x+1+5\left(x+1\right)+3\right)\)
\(=\left(x-1\right)\left(x^2+x+1+5x+5+3\right)\)
\(=\left(x-1\right)\left(x^2+6x+9\right)=\left(x-1\right)\left(x+3\right)^2\)
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) \(x^3-7x^2+9x+3x^2-21x+27=x\left(x^2-7x+9\right)+3\left(x^2-7x+9\right)=\left(x+3\right)\left(x^2-7x+9\right)\)
Phân tích đa thức thành nhân tử
x^2-2xy+y^2-2x+2y
x^2-4x+4-x^2y+2xy
ax^2-3axy-x^2+6xy-9y^2
2a^2x-5a^2y-4x^2+30xy-25y^2
a) Ta có: \(x^2-2xy+y^2-2x+2y\)
\(=\left(x-y\right)^2-2\left(x-y\right)\)
\(=\left(x-y\right)\left(x-y-2\right)\)
b) Ta có: \(x^2-4x+4-x^2y+2xy\)
\(=\left(x-2\right)^2-xy\left(x-2\right)\)
\(=\left(x-2\right)\left(x-2-xy\right)\)
c) Ta có: \(ax^2-3axy-x^2+6xy-9y^2\)
\(=ax\left(x-3y\right)-\left(x^2-6xy+9y^2\right)\)
\(=ax\left(x-3y\right)-\left(x-3y\right)^2\)
\(=\left(x-3y\right)\left(ax-x+3y\right)\)
d) Ta có: \(2a^2x-5a^2y-4x^2+30xy-25y^2\)
\(=a^2\left(2x-5y\right)-\left(4x^2-30xy+25y^2\right)\)
\(=a^2\left(2x-5y\right)-\left(2x-5y\right)^2\)
\(=\left(2x-5y\right)\left(a^2-2x+5y\right)\)
phân tích các đa thức sau thành nhân tử
a, x^2 - xz - 9y^2 + 3yz
b, x^3 - x^2 - 5x +125
c, x^3 + 2x^2 - 6x - 27
d, 12x^3 + 4x^2 - 27x - 9
a) \(x^2-xz-9y^2+3yz\)
\(=\left(x^2-9y^2\right)-\left(xz-3yz\right)\)
\(=\left(x-3y\right)\left(x+3y\right)-z\left(x-3y\right)\)
\(=\left(x-3y\right)\left(x+3y-z\right)\)
c) \(x^3+2x^2-6x-27\)
\(=\left(x^3-27\right)+\left(2x^2-6x\right)\)
\(=\left(x-3\right)\left(x^2-3x+9\right)+2x\left(x-3\right)\)
\(=\left(x-3\right)\left(x^2-3x+9+2x\right)\)
\(=\left(x-3\right)\left(x^2-x+9\right)\)
b) \(x^3-x^2-5x+125\)
\(=\left(x^3+125\right)-\left(x^2+5x\right)\)
\(=\left(x+5\right)\left(x^2-5x+25\right)-x\left(5+x\right)\)
\(=\left(x+5\right)\left(x^2-5x+25-x\right)\)
\(=\left(x+5\right)\left(x^2-6x+25\right)\)
giúp mình với:
phân tích đa thức thành nhân tử
a)x^2+4x-y^2+4
b)x^3-x^2-x+1
c)x^4+6x^2y+9y^2-1
d)2x^2+3x-5
e)x^2-7xy+10y^2
\(x^2+4x-y^2+4\)
\(=\left(x^2+4x+4\right)-y^2\)
\(=\left(x^2+2\right)^2-y^4\)
\(=\left(x^2+y^2+2\right)\left(x^2-y^2+2\right)\)
\(\left(x^2+4x+4\right)-y^2\)
\(=\left(x+2\right)^2-y^2\)
\(=\left(x+2+y\right)\left(x+2-y\right)\)
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