K
Khách

Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.

2 tháng 11 2018

\(x^3-3x^2+3x-y^3-1\)

\(=\left(x-1\right)^3-y^3\)

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

Đề bài là gì sao không ghi rõ?? 

17 tháng 8 2021

đề bài là rút gọn à

19 tháng 8 2020

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

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

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

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

= (x - 5)(x + y)
c, x2 - 5x + 5y - y2 = (x - y)(x + y) - 5(x - y)

= (x - y)(x + y - 5)
d, 5x3 - 5x2y - 10x2 + 10xy = 5x2(x - y) - 10x(x - y)

= 5x(x - y)(x - 2)
e, 27x3 - 8y3 = (3x - 2y)(9x2 + 6xy + 4y2)
f, x2 - y2 - x - y = (x - y)(x + y) - (x + y)

= (x + y)(x - y - 1)
g, x2 - y2 - 2xy + y2 = (x2 - 2xy + y2) - y2

= (x - y)2 - y2

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

= (x - 2)2 - y2

= (x - y - 2)(x + y - 2)
i, x3 + 3x2 + 3x + 1 - 27z3 = (x + 1)3 - 27z3

= (x+1-3z)(x2+2x+1+3xz+3z+9z2)
k, 4x2 + 4x - 9y2 + 1 = (2x + 1)2 - 9y2

= (2x - 3y + 1)(2x + 3y + 1)
m, x2 - 3x + xy - 3y = x(x - 3) + y(x - 3)

= (x - 3)(x + y)

19 tháng 8 2020

a) \(-x-y^2+x^2-y\)

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

\(=\left(x-y\right)\left(x+y\right)-\left(x+y\right).1\)

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

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

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

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

c) \(x^2-5x+5y-y^2\)

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

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

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

d) \(5x^3-5x^2y-10x^2+10xy\)

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

\(=5x\left[x\left(x-y\right)-2\left(x-y\right)\right]\)

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

e) \(27x^3-8y^3\)

\(=\left(3x\right)^3-\left(2y\right)^3\)

\(=\left(3x-2y\right)\left[\left(3x\right)^2+3x2y+\left(2y\right)^2\right]\)

\(=\left(3x-2y\right)\left(9x^2+6xy+4y^2\right)\)

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

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

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

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

g) \(x^2-y^2-2xy+y^2\)

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

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

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

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

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

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

\(=\left(x^2-2.2x+2^2\right)-y^2\)

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

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

i) \(x^6-y^6\)

\(=\left(x^3\right)^2-\left(y^3\right)^2\)

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

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

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