Phân tích đa thức thành nhân tử x^2 - y² + 3x + 3y
d x² - 4y² + 9x + 4
Phân tích mỗi đa thức sau thành nhân tử
a)x^3-2x^2y+xy^2+xy
b)x^3+4x^2y+4xy^2-9x
c)x^3-y^3+x-y
d)4x^2-4xy+2x-y+y^2
e)9x^2-3x+2y-4y^2
f)3x^2-6xy+3y^2-5x+5y
a) Xem lại đề
b) x³ - 4x²y + 4xy² - 9x
= x(x² - 4xy + 4y² - 9)
= x[(x² - 4xy + 4y² - 3²]
= x[(x - 2y)² - 3²]
= x(x - 2y - 3)(x - 2y + 3)
c) x³ - y³ + x - y
= (x³ - y³) + (x - y)
= (x - y)(x² + xy + y²) + (x - y)
= (x - y)(x² + xy + y² + 1)
d) 4x² - 4xy + 2x - y + y²
= (4x² - 4xy + y²) + (2x - y)
= (2x - y)² + (2x - y)
= (2x - y)(2x - y + 1)
e) 9x² - 3x + 2y - 4y²
= (9x² - 4y²) - (3x - 2y)
= (3x - 2y)(3x + 2y) - (3x - 2y)
= (3x - 2y)(3x + 2y - 1)
f) 3x² - 6xy + 3y² - 5x + 5y
= (3x² - 6xy + 3y²) - (5x - 5y)
= 3(x² - 2xy + y²) - 5(x - y)
= 3(x - y)² - 5(x - y)
= (x - y)[(3(x - y) - 5]
= (x - y)(3x - 3y - 5)
Phân tích đa thức thành nhân tử
\(x^4y-3x^3y^2+3x^2y^3+xy^4\)
\(x^4y-3x^3y^2+3x^2y^3+xy^4=xy\left(x^3-3x^2y+3xy^2+y^3\right)\)
Phân tích đa thức sau thành nhân tử
a ) 9(x+y-1)^2 - 4 (2x+3y+1)^2
b ) 3x^4y^2 +3x^3y^2 +3xy^2 +3y^2
c ) ( x+y )^3 - 1 -3xy( x + y -1)
d ) x^3 + 3x^2 + 3x +1 - 27z^3
Bài làm :
\(\text{a)}9\left(x+y-1\right)^2-4\left(2x+3y+1\right)^2\)
\(=\left(3x+3y-3\right)^2-\left(4x+6y+2\right)^2\)
\(=\left(3x+3y-3-4x-6y-2\right)\left(3x+3y-3+4x+6y+2\right)\)
\(=\left(-x-3y-5\right)\left(7x+9y-1\right)\)
\(\text{b)}3x^4y^2+3x^3y^2+3xy^2+3y^2\)
\(=\left(3x^4y^2+3xy^2\right)+\left(3x^3y^2+3y^2\right)\)
\(=3xy^2\left(x^3+1\right)+3y^2\left(x^3+1\right)\)
\(=\left(3xy^2+3y^2\right)\left(x^3+1\right)\)
\(=3y^2\left(x+1\right)\left(x+1\right)\left(x^2-x+1\right)\)
\(=3y^2\left(x+1\right)^2\left(x^2-x+1\right)\)
\(\text{c)}\left(x+y\right)^3-1-3xy\left(x+y-1\right)\)
\(=\left(x+y-1\right)\left[\left(x+y\right)^2+x+y+1\right]-3xy\left(x+y-1\right)\)
\(=\left(x+y-1\right)\left(x^2+2xy+y^2+x+y+1-3xy\right)\)
\(=\left(x+y-1\right)\left(x^2+x+y^2+y+1-xy\right)\)
\(d ) x^3+3x^2+3x+1-27z^3\)
\(=\left(x+1\right)^3-\left(3z\right)^3\)
\(=\left(x+1-3z\right)\left(x^2+2x+1+3xz+3z+9z^2\right)\)
Phân tích các đa thức sau thành nhân tử:
a,x^2-4xy+4y^2
b,4x^4+9y^2-12x^2y
c,x^2-3xy+x-3y
d,x^3-x^2-5x+125
e,x^2-y^2+6x+9
f,x^3+3x^2-9x-27
g,x^2-4y^2+4y-1
h,x^4+3x^3-9x-9
i,8x^3-36x^2y+54xy^2-27y^3
Phân tích các đa thức sau thành nhân tử:
a,x^2-4xy+4y^2
b,4x^4+9y^2-12x^2y
c,x^2-3xy+x-3y
d,x^3-x^2-5x+125
e,x^2-y^2+6x+9
f,x^3+3x^2-9x-27
g,x^2-4y^2+4y-1
h,x^4+3x^3-9x-9
i,8x^3-36x^2y+54xy^2-27y^3
Phân tích đa thức thành nhân tử :
a/ x^2 - 2x - 4y^2 - 4y
b/3x^2 - 3y^2 - 2(x - y)^2
phân tích đa thức thành nhân tử
a) 4x^2+8xy-3x-6y
b)x^4y-3x^3y^2+3x^2y^3+xy^4
c)x^3-5x^2-14x
d)x^4+4y^4
\(4x^2+8xy-3x-6y=4x\left(x+2y\right)-3\left(x+2y\right)=\left(4x-3\right)\left(x+2y\right)\)
\(x^4y-3x^3y^2+3x^2y^3-xy^4=xy\left(x^3-3x^2y+3xy^2-y^3\right)=xy\left(x-y\right)^3\)
\(x^3-5x^2-14x=x\left(x^2-5x-14\right)=x\left(x^2-7x+2x-14\right)=x\left[x\left(x-7\right)+2\left(x-7\right)\right]=x\left(x-7\right)\left(x+2\right)\)
\(x^4+4y^4=\left(x^2\right)^2+2\times x^2\times2y^2+\left(2y^2\right)^2-4x^2y^2=\left(x^2+2y^2\right)^2-\left(2xy\right)^2=\left(x^2-2xy+2y^2\right)\left(x^2+2xy+2y^2\right)\)
phân tích đa thức sau thành nhân tử
f , x mũ 3 - 4x mũ 2 - 9x + 36
g, 4x - 4y + x mũ 2 - 2xy + y mũ 2
h, x mũ 4 + x mũ 3 + x mũ 2 - 1
i, x mũ 2 - y mũ 2 - 4x - 4y
j, x mũ 3 - y mũ 3 - 3x + 3y
f) = x2( x - 4 ) - 9( x - 4 ) = ( x - 4 )( x - 3 )( x + 3 )
g) = 4( x - y ) + ( x - y )2 = ( x - y )( x - y + 4 )
h) = x3( x + 1 ) + ( x - 1 )( x + 1 ) = ( x + 1 )( x3 + x - 1 )
i) = ( x - y )( x + y ) - 4( x + y ) = ( x + y )( x - y - 4 )
j) = ( x - y )( x2 + xy + y2 ) - 3( x - y ) = ( x - y )( x2 + xy + y2 - 3 )
Trả lời:
f, x3 - 4x2 - 9x + 36 = ( x3 - 4x2 ) - ( 9x - 36 ) = x2 ( x - 4 ) - 9 ( x - 4 ) = ( x - 4 )( x2 - 9 ) = ( x - 4 )( x - 3 )( x + 3 )
g, 4x - 4y + x2 - 2xy + y2 = ( 4x - 4y ) + ( x2 - 2xy + y2 ) = 4 ( x - y ) + ( x - y )2 = ( x - y ) ( 4 + x - y )
h, x4 + x3 + x2 - 1 = ( x4 + x3 ) + ( x2 - 1 ) = x3 ( x + 1 ) + ( x - 1 )( x + 1 ) = ( x + 1 )( x3 + x - 1 )
i, x2 - y2 - 4x - 4y = ( x2 - y2 ) - ( 4x + 4y ) = ( x - y )( x + y ) - 4 ( x + y ) = ( x + y )( x - y - 4 )
j, x3 - y3 - 3x + 3y = ( x3 - y3 ) - ( 3x - 3y ) = ( x - y )( x2 + xy + y2 ) - 3 ( x - y ) = ( x - y )( x2 + xy + y2 - 3 )
f) x3-4x2-9x+36
=x2(x-4)-9(x-4)
=(x-4)(x2-9)
=(x-4)(x-3)(x+3)
g) 4x-4y+x2-2xy+y2
=4(x-y)+(x-y)2
=(x-y)(4+x-y)
h) x4+x3+x2-1
=x3(x+1)+(x-1)(x+1)
=(x+1)(x3+x-1)
i) x2-y2-4x-4y
=(x-y)(x+y)-4(x+y)
=(x+y)(x-y-4)
j) x3-y3-3x+3y
=(x-y)(x2+xy+y2)-3(x-y)
=(x-y)(x2+xy+y2-3)
#H
Phân tích đa thức sau thành nhân tử
a ) 9(x+y-1)^2 - 4 (2x+3y+1)^2
b ) 3x^4y^2 +3x^3y^2 +3xy^2 +3y^2
c ) ( x+y )^3 - 1 -3xy( x + y -1)
d ) x^3 + 3x^2 + 3x +1 - 27z^3
Giúp với ạ ! Cảm ơn
a) \(9\left(x+y-1\right)^2-4\left(2x+3y+1\right)^2\)
\(=\left(3x+3y-3\right)^2-\left(4x+6y+2\right)^2\)
\(=\left(3x+3y-3-4x-6y-2\right)\left(3x+3y-3+4x+6y+2\right)\)
\(=\left(-x-3y-5\right)\left(7x+9y-1\right)\)
b) \(3x^4y^2+3x^3y^2+3xy^2+3y^2\)
\(=\left(3x^4y^2+3xy^2\right)+\left(3x^3y^2+3y^2\right)\)
\(=3xy^2\left(x^3+1\right)+3y^2\left(x^3+1\right)\)
\(=\left(3xy^2+3y^2\right)\left(x^3+1\right)\)
\(=3y^2\left(x+1\right)\left(x+1\right)\left(x^2-x+1\right)\)
\(=3y^2\left(x+1\right)^2\left(x^2-x+1\right)\)
c) \(\left(x+y\right)^3-1-3xy\left(x+y-1\right)\)
\(=\left(x+y-1\right)\left[\left(x+y\right)^2+x+y+1\right]-3xy\left(x+y-1\right)\)
\(=\left(x+y-1\right)\left(x^2+2xy+y^2+x+y+1-3xy\right)\)
\(=\left(x+y-1\right)\left(x^2+x+y^2+y+1-xy\right)\)