Phân tích -> nhân tử : a. 6x^2y +4x b. 2x^2-6x+xy-3y
phân tích đa tử
a,xy+3x-7y-21
b,2xy-15-6x+5y
2x^2y+2x^2y-x-y
d,7x^3y-3xyz-21x^2+9z
e, 4x^2 -2x -y^2-y
f, 9x^2-25y^2 -6x+10y
a
\(xy+3x-7y-21\\ =\left(xy+3x\right)-\left(7y+21\right)\\ =x\left(y+3\right)-7\left(y+3\right)\\ =\left(y+3\right)\left(x-7\right)\)
b
\(2xy-15-6x+5y\\ =\left(2xy-6x\right)-\left(15-5y\right)\\ =2x\left(y-3\right)-5\left(3-y\right)\\ =2x\left(y-3\right)+5\left(y-3\right)\\ =\left(y-3\right)\left(2x+5\right)\)
c Đề phải là \(\left(2x^2y+2xy^2-x-y\right)\) mới phân tích được: )
\(=2xy\left(x+y\right)-\left(x+y\right)\\ =\left(x+y\right)\left(2xy-1\right)\)
d
\(7x^3y-3xyz-21x^2+9z\\ =\left(7x^3y-21x^2\right)-\left(3xyz-9z\right)\\ =7x^2\left(xy-3\right)-3z\left(xy-3\right)\\ =\left(xy-3\right)\left(7x^2-3z\right)\)
e
\(4x^2-2x-y^2-y\\ =\left(2x\right)^2-y^2-\left(2x+y\right)\\ =\left(2x-y\right)\left(2x+y\right)-\left(2x+y\right)\\ =\left(2x+y\right)\left(2x-y-1\right)\)
f
\(9x^2-25y^2-6x+10y\\ =\left(3x\right)^2-\left(5y\right)^2-\left(6x-10y\right)\\ =\left(3x-5y\right)\left(3x+5y\right)-2\left(3x-5y\right)\\ =\left(3x-5y\right)\left(3x+5y-2\right)\)
a: =x(y+3)-7(y+3)
=(y+3)(x-7)
b: \(=2xy-6x+5y-15\)
=2x(y-3)+5(y-3)
=(y-3)(2x+5)
c: \(=2xy\left(x+y\right)-\left(x+y\right)=\left(x+y\right)\left(2xy-1\right)\)
d: \(=xy\left(7x^2-3z\right)-3\left(7x^2-3z\right)\)
=(7x^2-3z)(xy-3)
e: =4x^2-y^2-2x-y
=(2x-y)(2x+y)-(2x+y)
=(2x+y)(2x-y-1)
f: =(3x-5y)(3x+5y)-2(3x-5y)
=(3x-5y)(3x+5y-2)
1.Phân tích thành nhân tử ( phương pháp nhóm nhiều hạng tử )
a. x^3 + 2x^2 - xy - 2y
b. xy - 5x + 3y^2 - 15y
c.2xy + 6x + y^2 + 3y
1.Phân tích thành nhân tử ( phương pháp nhóm nhiều hạng tử )
a. x^3 + 2x^2 - xy - 2y
\(=x^2\left(x+2\right)-y\left(x+2\right)\)
\(=\left(x+2\right)\left(x^2-y\right)\)
b. xy - 5x + 3y^2 - 15y
\(=xy+3y^2-5x-15y\)
\(=y\left(x+3y\right)-5\left(x+3y\right)\)
\(=\left(x+3y\right)\left(y-5\right)\)
c.2xy + 6x + y^2 + 3y
\(=2xy+y^2+6x+3y\)
\(=y\left(2x+y\right)+3\left(2x+y\right)\)
\(=\left(2x+y\right)\left(y+3\right)\)
a) \(x^3+2x^2-xy-2y\)
\(=\left(x^3-xy\right)+\left(2x^2-2y\right)\)
\(=x\left(x^2-y\right)+2\left(x^2-y\right)\)
\(=\left(x+2\right)\left(x^2-y\right)\)
\(=\left(x+2\right)\left(x+\sqrt{y}\right)\left(x-\sqrt{y}\right)\)
a) \(x^3+2x^2-xy-2y\)
\(=x^2\left(x+2\right)-y\left(x+2\right)\)
\(=\left(x+2\right)\left(x^2-y\right)\)
\(=\left(x+2\right)\left(x-\sqrt{y}\right)\left(x+\sqrt{y}\right)\)
b) \(xy-5x+3y^2-15y\)
\(=x\left(y-5\right)+3y\left(y-5\right)\)
\(=\left(y-5\right)\left(x+3\right)\)
c) \(2xy+6x+y^2+3y\)
\(=2x\left(y+3\right)+y\left(y+3\right)\)
\(=\left(y+3\right)\left(2x+y\right)\)
- làm ơn giúp mình với
phân tích đa thức thành nhân tử
a) 3x^3y^2+6x^2y^4
b) 16-4x^2
c) xy+xz+5x+5y
d) y^2-x^2+4x-4
a)
3x3y2+6x2y4=3x2y2*(x+y2)
b)
16-4x2=4*(4-x2)
c)
xy+xz+5x+5y=(xy+5y)+(xz+5x)
=y*(x+5)+x*(z+5)
=(x+5+z+5)*(y+x)
=5*(x+z)*(x+y)
phân tích đa thức thành nhân tử
\(a)3x^3+6x^2y \)
\(b)2x^3-6x^2\)
\(c)18x^2-20xy\)
\(d)xy+y^2-x-y \)
\(e)(x^2y^2-8)^2-1\)
\(f)x^2-7x-8\)
\(g)10x^2(2x-y)+6xy(y-2x)\)
\(h)x^2-2x+1-y^2\)
\(i)2x(x+2)+x^2(-x-2)\)
\(k)-9+6x-x^2\)
\(l)8xy-2x^2-8y^2\)
\(m)3x^2+5x-3y^2-5y\)
a) 3x³ + 6x²y
= 3x².(x + 2y)
b) 2x³ - 6x²
= 2x².(x - 2)
c) 18x² - 20xy
= 2x.(9x - 10y)
d) xy + y² - x - y
= (xy + y²) - (x + y)
= y(x + y) - (x + y)
= (x + y)(y - 1)
e) (x²y² - 8)² - 1
= (x²y² - 8 - 1)(x²y² - 8 + 1)
= (x²y² - 9)(x²y² - 7)
= (xy - 3)(xy + 3)(x²y² - 7)
f) x² - 7x - 8
= x² - 8x + x - 8
= (x² - 8x) + (x - 8)
= x(x - 8) + (x - 8)
= (x - 8)(x + 1)
a: \(3x^3+6x^2y\)
\(=3x^2\cdot x+3x^2\cdot2y=3x^2\left(x+2y\right)\)
b: \(2x^3-6x^2=2x^2\cdot x-2x^2\cdot3=2x^2\left(x-3\right)\)
c: \(18x^2-20xy=2x\cdot9x-2x\cdot10y=2x\left(9x-10y\right)\)
d: \(xy+y^2-x-y\)
\(=y\left(x+y\right)-\left(x+y\right)\)
\(=\left(x+y\right)\left(y-1\right)\)
e: \(\left(x^2y^2-8\right)^2-1\)
\(=\left(x^2y^2-8-1\right)\left(x^2y^2-8+1\right)\)
\(=\left(x^2y^2-7\right)\left(x^2y^2-9\right)\)
\(=\left(x^2y^2-7\right)\left(xy-3\right)\left(xy+3\right)\)
f: \(x^2-7x-8\)
\(=x^2-8x+x-8\)
\(=x\left(x-8\right)+\left(x-8\right)=\left(x-8\right)\left(x+1\right)\)
g: \(10x^2\left(2x-y\right)+6xy\left(y-2x\right)\)
\(=2x\cdot\left(2x-y\right)\cdot5x-2x\cdot\left(2x-y\right)\cdot3y\)
\(=2x\left(2x-y\right)\left(5x-3y\right)\)
h: \(x^2-2x+1-y^2\)
\(=\left(x-1\right)^2-y^2\)
\(=\left(x-1-y\right)\left(x-1+y\right)\)
i: \(2x\left(x+2\right)+x^2\left(-x-2\right)\)
\(=2x\left(x+2\right)-x^2\left(x+2\right)\)
\(=\left(x+2\right)\left(2x-x^2\right)=x\cdot\left(x+2\right)\left(2-x\right)\)
k: \(-x^2+6x-9=-\left(x^2-6x+9\right)\)
\(=-\left(x^2-2\cdot x\cdot3+3^2\right)=-\left(x-3\right)^2\)
l: \(-2x^2+8xy-8y^2\)
\(=-2\left(x^2-4xy+4y^2\right)\)
\(=-2\left(x-2y\right)^2\)
m: \(3x^2+5x-3y^2-5y\)
\(=3\left(x^2-y^2\right)+5\left(x-y\right)\)
\(=3\left(x-y\right)\left(x+y\right)+5\left(x-y\right)\)
\(=\left(x-y\right)\left(3x+3y+5\right)\)
g) 10x²(2x - y) + 6xy(y - 2x)
= 10x²(2x - y) - 6xy(2x - y)
= 2x(2x - y)(5x - 3y)
h) x² - 2x + 1 - y²
= (x² - 2x + 1) - y²
= (x - 1)² - y²
= (x - y - 1)(x + y - 1)
i) 2x(x + 2) + x² (-x - 2)
= 2x(x + 2) - x²(x + 2)
= x(x + 2)(2 - x)
k) -9 + 6x - x²
= -(x² - 6x + 9)
= -(x - 3)²
l) 8xy - 2x² - 8y²
= -2(x² - 4xy + 4y²)
= -2(x - 2y)²
m) 3x² + 5x - 3y² - 5y
= (3x² - 3y²) + (5x - 5y)
= 3(x² - y²) + 5(x - y)
= 3(x - y)(x + y) + 5(x - y)
= (x - y)[3(x + y) + 5]
= (x - y)(3x + 3y + 5)
Bài 1:Thực hiện phép tính a) x(3x^2 + 2x) b) (x + 3)^2 c) (x - 2)^3 Bài 2: Phân tính đa thức thành nhân tử a) 6x^3y - 9x^2y^2 b) 4x^2 - 25 c) x^2y - xy + 7x - 7y Bài 3: a) Tính nhanh giá trị biểu thức: M = 4x^2 - 20x + 25 tại x = 105/2 b) Tìm x, biết: x^3 - 1/9x = 0
Bài 1 Phân tich các đa thức sau thành nhân tử: a) x(2x -y) - y(2x -y) c) x^2- 3x + 3y -y^2 b) x²–6x - 7 d) x³- xy + 2y - 8
a: \(x\left(2x-y\right)-y\left(2x-y\right)=\left(2x-y\right)\left(x-y\right)\)
c: \(x^2-3x+3y-y^2\)
\(=\left(x-y\right)\left(x+y\right)-3\left(x-y\right)\)
\(=\left(x-y\right)\left(x+y-3\right)\)
b: \(x^2-6x-7=\left(x-7\right)\left(x+1\right)\)
a) \(x\left(2x-y\right)-y\left(2x-y\right)=\left(2x-y\right)\left(x-y\right)\)
b) \(x^2-6x-7=x\left(x-7\right)+\left(x-7\right)=\left(x-7\right)\left(x+1\right)\)
c) \(x^2-3x+3y-y^2=\left(x-y\right)\left(x+y\right)-3\left(x-y\right)=\left(x-y\right)\left(x+y-3\right)\)
d) \(x^3-xy+2y-8=\left(x-2\right)\left(x^2+2x+4\right)-y\left(x-2\right)\)
\(=\left(x-2\right)\left(x^2+2x+4-y\right)\)
a)x(2x - y) - y(2x - y)
= (x - y)(2x - y)
c)x2 - 3x + 3y - y2
= x2 - y2 - 3x + 3y
= (x + y)(x - y) - 3(x - y)
= (x + y - 3)(x - y)
b)x2 - 6x - 7
= x2 + x - 7x - 7
= x(x + 1) - 7(x + 1)
= (x - 7)(x + 1)
d)x3 - xy + 2y - 8
= x3 - 8 - xy + 2y
= x3 - 23 - y(x - 2)
= (x - 2)(x2 + 2x + 4) - y (x - 2)
= (x - 2 - y)(x2 + 2x + 4)
Phân tích đa thức thành nhân tử (bằng kĩ thuật bổ sung hằng đẳng thức)
a, 2a2 + 5ab - 3b2 - 7b-2
b,2x2 - 7xy + x + 3y2 - 3y
c,6x2 - xy - 2y2 + 3x - 2y
d,4x2 - 4xy - 3y2 - 2x + 3y
e,2x2 - 3xy - 4x - 9y2 - 6y
f,3x2 - 5xy + 2y2 + 4x - 4y
a. \(2a^2+5ab-3b^2-7b-2\)
\(=\left(2a^2+6ab+2a\right)-\left(ab+3b^2+b\right)-\left(2a+6b+2\right)\)
\(=2a\left(a+3b+1\right)-b\left(a+3b+1\right)-2\left(a+3b+1\right)\)
\(=\left(2a-b-2\right)\left(a+3b+1\right)\)
b. \(2x^2-7xy+x+3y^2-3y\)
\(=\left(2x^2-xy\right)-\left(6xy-3y^2\right)+\left(x-3y\right)\)
\(=x\left(2x-y\right)-3y\left(2x-y\right)+\left(x-3y\right)\)
\(=\left(x-3y\right)\left(2x-y\right)+\left(x-3y\right)\)
\(=\left(x-3y\right)\left(2x-y+1\right)\)
c. \(6x^2-xy-2y^2+3x-2y\)
\(=\left(6x^2+3xy\right)-\left(4xy-2y^2\right)+\left(3x-2y\right)\)
\(=3x\left(2x+y\right)-2y\left(2x+y\right)+\left(3x-2y\right)\)
\(=\left(3x-2y\right)\left(2x+y\right)+\left(3x-2y\right)\)
\(=\left(3x-2y\right)\left(2x+y+1\right)\)
Phân tích đa thức thành nhân tử:
a) x^3-6x^2-x+30
b) x^4_6x^3+27x^2-54x+32
c) 2x^2+xy-y^2
d) (x-2y)^2-x+2y-30
e) (x^2+4x+8)^2-3x(x^2+4x+8)+2x^2
Phân tích thành nhân tử bằng kĩ thuật bổ sung hằng đẳng thức
x^2-4xy-x+3y^2+3y
x^2+4xy+2x+3y^2+6y
6x^2+xy-7x-2y^2+7y-5
6a^2-ab-2b^2+a+4b