Phân tích da thức thành nhân tử :
a ) 6a^2y - 3aby +4a^2x - 2abx
b ) ax -bx -2cx -2a +2b +4c
c ) x^9 +1
d ) 25x^2 - 20xy +4y^2
e )x^2 +2xy +y^2 - 25
Phân tích đa thức sau thành nhân tử
a) (a^2+b^2)^2-4a^2b^2
b) 3x^2-3xy-5x+5y
c) -x^3+3x^2 -3x+1
d) 2x^2+4xy+2y^2- 8z^2
e) a^3-a^2-a+1
f) x^3-2xy-x^2y+2y^2
e) Ta có: \(a^3-a^2-a+1\)
\(=a^2\left(a-1\right)-\left(a-1\right)\)
\(=\left(a-1\right)\left(a^2-1\right)\)
\(=\left(a-1\right)^2\cdot\left(a+1\right)\)
f) Ta có: \(x^3-2xy-x^2y+2y^2\)
\(=x^2\left(x-y\right)-2y\left(x-y\right)\)
\(=\left(x-y\right)\left(x^2-2y\right)\)
a) \(\left(a^2+b^2\right)^2-4a^2b^2=\left(a^2+b^2+2ab\right)\left(a^2+b^2-2ab\right)=\left(a+b\right)^2.\left(a-b\right)^2\)
b) \(3x^2-3xy-5x+5y=3x\left(x-y\right)-5\left(x-y\right)=\left(x-y\right)\left(3x-5\right)\)
c) \(-x^3+3x^2-3x+1=\left(1-x\right)^3\)
d) Đề sai ko ???
e) \(a^3-a^2-a+1=a^2\left(a-1\right)-\left(a-1\right)=\left(a-1\right)\left(a^2-1\right)=\left(a-1\right)^2\left(a+1\right)\)
f) \(x^3-2xy-x^2y+2y^2=x^2\left(x-y\right)-2y\left(x-y\right)=\left(x-y\right)\left(x^2-2y\right)\)
a, \(=\left(a^2+b^2-2ab\right)\left(a^2+b^2+2ab\right)=\left(\left(a-b\right)\left(a+b\right)\right)^2=\left(a^2-b^2\right)^2\)
\(b,=3x\left(x-y\right)-5\left(x-y\right)=\left(x-y\right)\left(3x-5\right)\)
\(c,=-\left(x^2-3x^2+3x-1\right)=-\left(x-1\right)^3\)
\(d,=2\left(x^2+2xy+y^2-4z^2\right)=2\left(\left(x+y\right)^2-4z^2\right)=2\left(x+y-2z\right)\left(x+y+2z\right)\)
\(e,=a^2\left(a-1\right)-\left(a-1\right)=\left(a-1\right)\left(a^2-1\right)\)
\(f,=x^2\left(x-y\right)-2y\left(x-y\right)=\left(x^2-2y\right)\left(x-y\right)\)
Phân tích đa thức sau bằng phương pháp nhóm hạng tử
1) x ( a - b ) + a - b ; 2) x - y - a( x - y ) ; 3) a( x + y ) - x - y ; 4) x( a - b ) - a + b ; 5) x\(^2\) + xy - 2x - 2y
6) 10ax - 5ay + 2x - y ; 7) 2a\(^{^2}\) x - 5by - 5a\(^2\) y + 2bx ; 8) 2ax\(^2\)- bx\(^2\) - 2ax + bx + 4a - 2b ; 9) 2ax - bx + 3cx - 2a + b - 3c
10) ax - bx - 2cx - 2a + 2b + 4c
1, x(a-b)+a-b 2, x-y-a(x-y) 3, a(x+y)-x-y 4, x(a-b)-a+b 5, x2+xy-2x-2y 6, 10ax-5ay+2x-y
= x(a-b)+(a-b) =(x-y)-a(x-y) =a(x+y)-(x+y) =x(a-b)-(a-b) =(x2+xy)-(2x+2y) =(10ax+2x)-(5ay+y)
=(a-b)(x+1) =(x-y)(1-a) =(x+y)(a-1) =(a-b)(x-1) =x(x+y)-2(x+y) =2x(5a+1)-y(5a+1)
=(x+y)(x-2) =(5a+1)(2x-y)
7, 2a2x-5by-5a2y+2bx 8, 2ax2-bx2-2ax+bx+4a-2b 9, 2ax-bx+3cx-2a+b-3c 10, ax-bx-2cx-2a+2b+4c
=(2a2x+2bx)-(5by+5a2y) =(2ax2-bx2)-(2ax-bx)+(4a-2b) =(2ax-2a)-(bx-b)+(3cx-3c) =(ax-2a)-(bx-2b)-(2cx-4c)
=2x(a2+b)-5y(b+a2) =x2(2a-b)-x(2a-b)+2(2a-b) =2a(x-1)-b(x-1)+3c(x-1) =a(x-2)-b(x-2)-2c(x-2)
=(a2+b)(2x-5y) =(2a-b)(x2-x+2) =(x-1)(2a-b+3c) =(x-2)(a-b-2c)
Phân tích thành nhân tử :
1, \(2ax^2-bx^2-2ax+bx+4a-2b\)
2, \(ax^2y-bx^2y-ax+bx+2a-2b\)
3, \(49\cdot\left(x-y\right)^2-25\cdot\left(y-1\right)^2\)
Phân tích đa thức thành nhân tử
2x+2y-x^2-xy
x^2y+xy^2-4x-4y
5x-5y+ax-ay
a^3-a^2x-ax+xy
x^2+4x-2xy-4y+y^2
phân tích đa thức thành nhân tử
a)25x^2-4a^2+12ab-9b^2
b)x^3+x^2y-xy^2-y^3
\(a.25^2-4a^2+12ab-9b^2\\ =25^2-\left(4a^2+12ab-9b^2\right)\\ =25^2-\left(2a-3b\right)^2\\ =\left(25-2a+3b\right)\left(25+2a-3b\right)\\ b.x^3+x^2y-xy^2-y^3\\ =x^2\left(x+y\right)-y^2\left(x+y\right)\\ =\left(x+y\right)\left(x^2-y^2\right)\\ =\left(x+y\right)\left(x+y\right)\left(x-y\right)\\ =\left(x+y\right)^2\left(x-y\right)\)
a: Ta có: \(25x^2-4a^2+12ab-9b^2\)
\(=25x^2-\left(2a-3b\right)^2\)
\(=\left(5x-2a+3b\right)\left(5x+2a-3b\right)\)
b: Ta có: \(x^3+x^2y-xy^2-y^3\)
\(=\left(x-y\right)\left(x^2+xy+y^2\right)+xy\left(x-y\right)\)
\(=\left(x-y\right)\left(x+y\right)^2\)
Bài 4: đặt nhân tử chung
c)x(x-2)+(x-2)2
d) 2x(x-y)2-5(y-x)
Bài 5 :
a) x2-6x-2xy+12y
b) 10ax-5ay-2x+y
c)x4+x3y-x-y
d) x3+2x2-4x-8
e) xy-5x-y2+5y
f) ax-bx-2cx-2a+2b+4c
g) 5x2y+5xy2-b2x-b2y
h) 4x3-4x2-9x+9
Bài 4
c) x(x - 2) + (x - 2)²
= (x - 2)(x + x - 2)
= (x - 2)(2x - 2)
= 2(x - 2)(x - 1)
d) 2x(x - y)² - 5(y - x)
= 2x(x - y)² + 5(x - y)
= (x - y)(2x + 5)
Bài 5
a) x² - 6x - 2xy + 12y
= (x² - 6x) - (2xy - 12y)
= x(x - 6) - y(x - 6)
= (x - 6)(x - y)
b) 10ax - 5ay - 2x + y
= (10ax - 5ay) - (2x - y)
= 5a(2x - y) - (2x - y)
= (2x - y)(5a - 1)
c) x⁴ + x³y - x - y
= (x⁴ + x³y) - (x + y)
= x³(x + y) - (x + y)
= (x + y)(x³ - 1)
= (x + y)(x - 1)(x² + x + 1)
d) x³ + 2x² - 4x - 8
= (x³ + 2x²) - (4x + 8)
= x²(x + 2) - 4(x + 2)
= (x + 2)(x² - 4)
= (x + 2)(x + 2)(x - 2)
= (x + 2)²(x - 2)
e) xy - 5x - y² + 5y
= (xy - 5x) - (y² - 5y)
= x(y - 5) - y(y - 5)
= (y - 5)(x - y)
f) ax - bx - 2cx - 2a + 2b + 4c
= (ax - bx - 2cx) - (2a - 2b - 4c)
= x(a - b - 2c) - 2(a - b - 2c)
= (a - b - 2c)(x - 2)
g) 5x²y + 5xy² - b²x - b²y
= (5x²y + 5xy²) - (b²x + b²y)
= 5xy(x + y) - b²(x + y)
= (x + y)(5xy - b²)
h) 4x³ - 4x² - 9x + 9
= (4x³ - 4x²) - (9x - 9)
= 4x²(x - 1) - 9(x - 1)
= (x - 1)(4x² - 9)
= (x - 1)(2x - 3)(2x + 3)
phân tích đa thức thành nhân tử
a, \(8xy^2-12x^2y+20xy\)
b,\(2x^2-50\)
c, \(x^2-6x+9-4y^2\)
a,=\(4xy\left(2y-3x+5\right)\)
b,=\(2\left(x^2-25\right)=2\left(x+5\right)\left(x-5\right)\)
c,=\(\left(x-3\right)^2-\left(2y\right)^2=\left(x-3-2y\right)\left(x-3+2y\right)\)
Phân tích đa thức thành nhân tử : 6a2y - 3aby + 4a2x - 2aby
\(25\left(x-3\right)^2-\left(2x-7\right)^2\)(*)
Đặt \(x-3=t\)và \(2x-7=z\)thay vào (*) ta được:
\(25t^2-z^2\)
\(=\left(5t-z\right)\left(5t+z\right)\)thay t=x-3 và y=2x-7 ta được:
\(=\left(5x-15-2x+7\right)\left(5x-15+2x-7\right)\)
\(=\left(3x-8\right)\left(7x-22\right)\)
C2 nhân ra rồi phân tích
\(25\left(x-3\right)^2-\left(2x-7\right)^2\)
\(=5^2.\left(x-3\right)^2-\left(2x-7\right)^2\)
\(=\left[5.\left(x-3\right)\right]^2-\left(2x-7\right)^2\)
\(=\left[5\left(x-3\right)-\left(2x-7\right)\right]\left[5\left(x-3\right)+\left(2x-7\right)\right]\)
\(=\left(5x-15-2x+7\right)\left(5x-15+2x-7\right)\)
\(=\left(3x-8\right)\left(7x-22\right)\)
Phân tích đa thức dau thành nhân tử
a)x^2+2x-4y^2-4y
b)x^4-6x^3+54x-81
c)ax^2+ax-bx^2-bx-a+b
d)(x^2+y^2-2)-(2xy-2)^2
a)x^2+2x-4y^2-4y
=(x2-4y2)+(2x-4y)
=(x-2y)(x+2y)+2.(x-2y)
=(x-2y)(x+2y+2)
b)x^4-6x^3+54x-81
=(x4-81)+(-6x3+54x)
=(x2-9)(x2+9)-6x.(x2-9)
=(x2-9)(x2+9-6x)
=(x-3)(x+3)(x-3)2
=(x-3)3(x+3)
c)ax^2+ax-bx^2-bx-a+b
=(ax2-bx2)+(ax-bx)+(-a+b)
=x2.(a-b)+x.(a-b)-(a-b)
=(a-b)(x2+x+1)