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26 tháng 6 2016

\(a,x^2-y^2-2x+2y=\left(x^2-y^2\right)-\left(2x-2y\right)=\left(x-y\right)\left(x+y\right)-2\left(x-y\right)=\left(x-y\right)\left(x+y-2\right).\) \(b,2x+2y-x^2-xy=2\left(x+y\right)-x\left(x+y\right)=\left(x+y\right)\left(2-x\right)\)

\(c,3a^2-6ab+3b^2-12c^2=3\left(a^2-2ab+b^2-4c^2\right)=3.\left(\left(a-b\right)^2-\left(2c\right)^2\right)\)

                                                     \(=3\left(a-b-2c\right).\left(a-b+2c\right)\)

\(d,x^2-25+y^2-2xy=\left(x^2-2xy+y^2\right)-5^2=\left(x-y\right)^2-5^2\)

                                           \(=\left(x-y+5\right)\left(x-y-5\right)\)

\(e,a^2+2ab+b^2-ac-bc=\left(a+b\right)^2-c\left(a+b\right)=\left(a+b\right)\left(a+b-c\right)\)

\(f,x^2-2x-4y^2-4y=\left(x^2-4y^2\right)-\left(2x+4y\right)=\left(x-2y\right)\left(x+2y\right)-2\left(x+2y\right)\)

                                         \(=\left(x+2y\right)\left(x-2y-2\right)\)

\(h,x^2\left(x-1\right)+16\left(1-x\right)=x^2\left(x-1\right)-16\left(x-1\right)=\left(x-1\right)\left(x^2-16\right)=\)

                                                    \(=\left(x-1\right)\left(x-4\right)\left(x+4\right)\)

3 tháng 10 2016

1)

x2-y2-2x+2y

=(x-y)(x+y)-2(x-y)

=(x-y)(x+y-2)

2)

2x+2y-x2-xy

=2(x+y)-x(x+y)

=(2-x)(x+y)

3)

3a2-6ab+3b2-12c2

=3(a2-2ab+b2)-3(4c2)

=3(a-b)2-3(4c2)

=3[(a-b)2-4c2 ]

=3(a-b-2c)(a-b+2c)

4)

x2-25+y2+2xy

=(x+y)2-25

=(x+y-5)(x+y+5)

3 tháng 10 2016

1) x^2 - y^2 - 2x + 2y= ( x^2 - y^2) - ( 2x + 2y) = (x-y -2 ) (x+y)

2) 2x + 2y - x^2 - xy = 2 (x+y) - x(x+y) = (2-x)(x+y)

4) x^2 - 25 + y^2 +2xy = x^2 + 2xy + y^2 - 25 = (x+y)^2 - 5^2 = (x+y-5)(x+y+5)

5) a^2 + 2ab +b^2-ac-bc= (a+b)^2- ac + bc = (a+b)^2 - c(a+b) = (a+b)(a+b-c)

6) x^2 - 2x - 4y^2 - 4y = (x^2 - 4y^2) - (2x+4y) = (x - 2y)(x+2y) - 2 (x+2y) = (x-2y-2)(x+2y)

7) x^2y - x^3 - 9y + 9x = x^2 (y-x) - 9(y-x) = (x^2 - 9)(y-x)= (x^2 - 3^2)(y-x) = (x-3)(x+3)(y-x)

- Xl câu 3 , 8 t hk biết lm

5 tháng 7 2017

a) Ta có : x2 - y2 - 2x + 2y

= (x2 - y2) - (2x - 2y)

= (x - y)(x + y) - 2(x - y)

= (x - y)(x + y - 2)

5 tháng 7 2017

a, x2 - y2 - 2x + 2y

= ( x2 - y2 ) - ( 2x - 2y )

= ( x - y ).( x + y ) - 2.( x - y )

= ( x - y ).( x + y - 2 )

14 tháng 8 2019

\(x^2-y^2-2x+2y=\left(x+y\right)\left(x-y\right)-2\left(x-y\right)=\left(x+y-2\right)\left(x-y\right)\) \(2x+2y-x^2-xy=2\left(x+y\right)-x\left(x+y\right)=\left(2-x\right)\left(x+y\right)\)

\(3a^2-6ab+3b^2-12c^2=3\left(a^2-2ab+b^2-4c^2\right)=3\left(a-b\right)^2-3\left(2c\right)^2=3\left(a-b+2c\right)\left(a-b-2c\right)\) \(x^2-25+y^2+2xy=\left(x+y\right)^2-25=\left(x+y-5\right)\left(x+y+5\right)\)

14 tháng 8 2019

\(a^2+2ab+b^2-ac-bc=\left(a+b\right)^2-c\left(a+b\right)=\left(a+b\right)\left(a+b-c\right)\)

\(x^2-2x+1-4y^2-4y-1=\left(x-1\right)^2-\left(2y+1\right)^2=\left(x+2y\right)\left(x-2y-2\right)\)\(x^2\left(x-1\right)-16\left(x-1\right)=\left(x-1\right)\left(x^2-16\right)=\left(x-1\right)\left(x+4\right)\left(x-4\right)\) \(x^2y-x^3-9y+9x=x^2\left(y-x\right)-9\left(y-x\right)=\left(y-x\right)\left(x^2-9\right)\left(y-x\right)\left(x-3\right)\left(x+3\right)\)

18 tháng 8 2020

cảm ơn bạn nha

a) Ta có: 10(x-y)-8y(y-x)

\(=10\left(x-y\right)+8y\left(x-y\right)\)

\(=2\left(x-y\right)\left(5+4y\right)\)

d) Ta có: \(x^2y-x^3-9y+9x\)

\(=x^2\left(y-x\right)-9\left(y-x\right)\)

\(=\left(y-x\right)\left(x^2-9\right)\)

\(=\left(y-x\right)\left(x-3\right)\left(x+3\right)\)

e) Ta có: \(2x+2y-x^2-xy\)

\(=2\left(x+y\right)-x\left(x+y\right)\)

\(=\left(x+y\right)\left(2-x\right)\)

f) Ta có: \(x^2-25+y^2+2xy\)

\(=\left(x+y\right)^2-5^2\)

\(=\left(x+y-5\right)\left(x+y+5\right)\)

g) Ta có: \(x^2-2x-4y^2-4y\)

\(=\left(x-2y\right)\left(x+2y\right)-2\left(x+2y\right)\)

\(=\left(x+2y\right)\left(x-2y-2\right)\)

h) Ta có: \(x^2\left(x-1\right)+16\left(1-x\right)\)

\(=x^2\left(x-1\right)-16\left(x-1\right)\)

\(=\left(x-1\right)\left(x^2-16\right)\)

\(=\left(x-1\right)\left(x-4\right)\left(x+4\right)\)

5 tháng 10 2020

a) x2-y2-2x+2y

=(x+y)(x-y)-2(x-y)

=(x-y)(x+y-2)

b) 2x + 2y - x2 -xy

=2(x+y) - x(x+y)

=(x+y)(2-x)

c) 3a2 - 6ab + 3b2 - 12c2

= 3(a2+b2) -3(2ab+4c2)

= 3(a2+b2-2ab-4c2)

d) x2 - 25 + y2 + 2xy

= x2 + 2xy + y2 -25

= (x+y)2 - 52

= (x+y+5)(x+y-5)

e) x2y - x3 - 9y + 9x

= (9x - x3)+(x2y -9y)

= x(9-x2)+y(x2 - 9)

= x(9-x2)-y(9-x2)

= (9-x2)(x-y)

f) x2-2x-4y2-4y

= x2-4y2-2(x+2y)

=(x+2y)(x-4y)-2(x+2y)

=(x+2y)(x-4y-2)

câu g trùng với câu e

h) x2(x-1)+16(1-x)

= x2(x-1)-16(x-1)

= (x2-16)(x-1)

= (x+4)(x-4)(x-1)

1 tháng 10 2018

a)\(x^2-y^2-2x+2y=\left(x^2-2x+1\right)-\left(y^2-2y+1\right)\)

\(=\left(x-1\right)^2-\left(y-1\right)^2=\left(x-1+y-1\right)\left(x-1-y+1\right)\)

\(=\left(x+y-2\right)\left(x-y\right)\)

b)\(3a^2-6ab+3b^2-12c^2=3\left(a^2-2ab+b^2-4c^2\right)\)\(=3\left[\left(a-b\right)^2-\left(2c\right)^2\right]\)

\(=3\left(a-b+2c\right)\left(a-b-2c\right)\)

12 tháng 10 2021

Bài 2: 

a: \(3x^2-3xy=3x\left(x-y\right)\)

b: \(x^2-4y^2=\left(x-2y\right)\left(x+2y\right)\)

c: \(3x-3y+xy-y^2=\left(x-y\right)\left(3+y\right)\)

d: \(x^2-y^2+2y-1=\left(x-y+1\right)\left(x+y-1\right)\)

18 tháng 10 2021

ỳtct7ct7c7c7t79tc9

 

24 tháng 5 2018

Bài làm:

a) x2 - y2 - 2x + 2y = (x - y)(x + y) - (2x - 2y)

= (x - y)(x + y) - 2(x - y)

= [(x + y) - 2].(x - y)

= (x + y - 2)(x - y)

c)3a2 - 6ab + 3b2 - 12c2 = (3a2 - 6ab + 3b2) - 12c2

= 3(a2 - 2ab + b2) - 12c2

= 3[(a - b)2] - 12c2

= 3[(a - b)2 - 4c2]

= 3[(a - b)2 - (2c)2]

= 3[(a - b - c) - (a - b + c)]

= 3(a - b - c - a + b - c)

= 3(-2c)

= -6c

d)x2 - 5 + y2 + 2xy = (x2 + 2xy + y2) - 5

= (x + y)2 - 5

= (x + y)2 -(\(\sqrt{5}\))2

= (x + y - \(\sqrt{5}\)) - (x + y + \(\sqrt{5}\))

= x + y - \(\sqrt{5}\) - x - y -\(\sqrt{5}\)

= -2\(\sqrt{5}\)

e) a2 + 2ab + b2 - ac - bc = (a2 + 2ab + b2) - (ac + bc)

= (a + b)2 - c(a + b)

= [(a + b) - c].(a + b)

= (a + b - c)(a + b)

Còn câu b) và câu f) Vàng sẽ nghĩ sau :v

24 tháng 5 2018

Tiếp câu f luôn !

\(x^2-2x-4y^2-4y\)

\(=\left(x^2-4y^2\right)-\left(2x+4y\right)\)

\(=\left(x-2y\right)\left(x+2y\right)-2\left(x+2y\right)\)

\(=\left(x+2y\right)\left(x-2y-2\right)\)

a: =(6x)^2-(3x-2)^2

=(6x-3x+2)(6x+3x-2)

=(9x-2)(3x+2)

d: \(=\left[\left(x+1\right)^2-\left(x-1\right)^2\right]\left[\left(x+1\right)^2+\left(x-1\right)^2\right]\)

\(=4x\cdot\left[x^2+2x+1+x^2-2x+1\right]\)

=8x(x^2+1)

e: =(4x)^2-2*4x*3y+(3y)^2

=(4x-3y)^2

f: \(=-\left(\dfrac{1}{4}x^4-2\cdot\dfrac{1}{2}x^2\cdot2y^3+4y^6\right)\)

\(=-\left(\dfrac{1}{2}x^2-2y^3\right)^2\)

g: =(4x)^3+1^3

=(4x+1)(16x^2-4x+1)

k: =x^3(27x^3-8)

=x^3(3x-2)(9x^2+6x+4)

l: =(x^3-y^3)(x^3+y^3)

=(x-y)(x+y)(x^2-xy+y^2)(x^2+xy+y^2)