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16 tháng 7 2017

Đoàn Đức Hiếu

16 tháng 7 2017

h cần ko vạy thui h đnag chán chiều làm :D

18 tháng 7 2017

a, Theo bài ra ta có:

\(=x^3-x-2x+2\)

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

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

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

b, theo bài ra ta có:

\(=x^3-3x^2-\left(2x^2-6x\right)-\left(3x-9\right)\)

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

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

c,Theo bài ra ta có:

\(=x^3+5x^2+3x^2+15x+2x+10\)

\(=x^2\left(x+5\right)+3x\left(x+5\right)+2\left(x+5\right)\)

\(=\left(x+5\right)\left(x^2+3x+2\right)\)

\(=\left(x+5\right)\left(x^2+x+2x+2\right)=\left(x+5\right)\left(x\left(x+1\right)+2\left(x+1\right)\right)\)

\(=\left(x+5\right)\left(x+1\right)\left(x+2\right)\)

CHÚC BẠN HỌC TỐT...........

18 tháng 7 2017

a) \(x^3-3x+2\)

= \(x^3-x^2+x^2-x-2x+2\)

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

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

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

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

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

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

b) \(x^3-5x^2+3x+9\)

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

= \(x^2\left(x+1\right)-6x\left(x+1\right)+9\left(x+1\right)\)

= \(\left(x+1\right)\left(x^2-6x+9\right)\)

= \(\left(x+1\right)\left(x-3\right)^2\)

c) \(x^3+8x^2+17x+10\)

= \(x^3+x^2+7x^2+7x+10x+10\)

= \(x^2\left(x+1\right)+7x\left(x+1\right)+10\left(x+1\right)\)

= \(\left(x+1\right)\left(x^2+7x+10\right)\)

= \(\left(x+1\right)\left(x^2+2x+5x+10\right)\)

= \(\left(x+1\right)\left[x\left(x+2\right)+5\left(x+2\right)\right]\)

= \(\left(x+1\right)\left(x+2\right)\left(x+5\right)\)

d) \(x^3-3x^2+6x+4\)

Câu này đúng là sai đề rồi, mình sửa + làm bên dưới:

\(x^3+3x^2+6x+4\)

= \(x^3+x^2+2x^2+2x+4x+4\)

= \(x^2\left(x+1\right)+2x\left(x+1\right)+4\left(x+1\right)\)

= \(\left(x+1\right)\left(x^2+2x+4\right)\)

Học tốt nhé :))

18 tháng 6 2017

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

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

= \(z^2\)

18 tháng 6 2017

Ta có:(x + y + z)2 - 2(x + y + z) (x + y) + (x + y)2

=[(x+y+z)-(x+y)]2=z2

10 tháng 9 2018

a) \(x^2-6x+3\)

\(=x^2-2.x.3+9-6\)

\(=\left(x-3\right)^2-\left(\sqrt{6}\right)^2\)

\(=\left(x-3-\sqrt{6}\right)\left(x-3+\sqrt{6}\right)\)

b) \(9x^2+6x-8\)

\(=\left(3x\right)^2+2.3x+1-9\)

\(=\left(3x+1\right)^2-3^2\)

\(=\left(3x+1-3\right)\left(3x+1+3\right)\)

\(=\left(3x-2\right)\left(3x+4\right)\)

10 tháng 9 2018

d) \(x^3+6x^2+11x+6\)

\(=x^3+3x^2+3x^2+9x+2x+6\)

\(=x^2\left(x+3\right)+3x\left(x+3\right)+2\left(x+3\right)\)

\(=\left(x+3\right)\left(x^2+3x+2\right)\)

\(=\left(x+3\right)\left(x^2+x+2x+2\right)\)

\(=\left(x+3\right)\left[x\left(x+1\right)+2\left(x+1\right)\right]\)

\(=\left(x+3\right)\left(x+1\right)\left(x+2\right)\)

e) \(x^3+4x^2-29x+24\)

\(=x^3+8x^2-4x^2-32x+3x+24\)

\(=x^2\left(x+8\right)-4x\left(x+8\right)+3\left(x+8\right)\)

\(=\left(x+8\right)\left(x^2-4x+3\right)\)

\(=\left(x+8\right)\left(x^2-3x-x+3\right)\)

\(=\left(x+8\right)\left[x\left(x-3\right)-\left(x-3\right)\right]\)

\(=\left(x+8\right)\left(x-3\right)\left(x-1\right)\)

28 tháng 6 2017

\(\left(a+b\right)^3+\left(b+c\right)^3+\left(a+c\right)^3-3\left(a+b\right)\left(b+c\right)\left(c+a\right)\)

\(=2a^3-6abc+2b^3+2c^3\)

28 tháng 6 2017

Khỏi ghi lại đề:

\(=a^3+3a^2b+3ab^2+b^3+b^3+3b^2c+3bc^2+c^3+c^3+3c^2a+3a^2c+a^3-3.\left(2abc+a^2b+ac^2+a^2c+b^2c+ab^2+bc^2\right)\)

\(=2a^3+2b^3+2c^3-6abc\)

22 tháng 9 2017

Sao bạn không tự làm bớt đi , bài dễ mà

a: \(9x^2-6x+3\)

\(=\left(9x^2-6x+1\right)+2\)

\(=\left(3x-1\right)^2+2\ge2\)

b: \(6x-x^2+1\)

\(=-\left(x^2-6x-1\right)\)

\(=-\left(x^2-6x+9-10\right)\)

\(=-\left(x-3\right)^2+10\le10\)

13 tháng 12 2016

a) \(a^4+4\)

\(=a^4+4a^2+4-4a^2\)

\(=\left(a^2+2\right)^2+\left(2a\right)^2\)

\(=\left(a^2+2a+2\right)\left(a^2-2a+2\right)\)

b) \(\left(x+y+z\right)^3-x^3-y^3-z^3\)

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

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

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

\(=3\left(x+y\right)\left(xy+xz+yz+z^2\right)\)

\(=3\left(x+y\right)\left[x\left(y+z\right)+z\left(y+z\right)\right]\)

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

 

 

29 tháng 10 2017

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

\\(=a^3+b^3+c^3+3a^2b+3ab^2+3a^2c+3ac^2+3b^2c+3bc^2+6abc-a^3-b^3-c^3\\)\\(=3\\left(3a^2b+3ab^2+3a^2c+3ac^2+3b^2c+3bc^2+6abc\\right)\\)

\\(=3\\left(abc+a^2b+a^2c+ac^2+b^2c+ab^2+abc+bc^2\\right)\\)

\\(=3\\left[ab\\left(a+c\\right)+ac\\left(a+c\\right)+b^2\\left(a+c\\right)+bc\\left(a+c\\right)\\right]\\)

\\(=3\\left(a+c\\right)\\left(ab+ac+bc+b^2\\right)\\)

\\(=3\\left(a+c\\right)\\left[a\\left(b+c\\right)+b\\left(b+c\\right)\\right]\\)

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

b) 4a2b2-(a2  +b2-c2)2

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

=[(a+b)2-c2][c2-(a-b)2]

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

 

30 tháng 10 2017

a) \(\left(a+b+c\right)^3-a^3-b^3-c^3\)

\(=a^3+b^3+c^3+3ab\left(a+b\right)+3bc\left(b+c\right)+3ca\left(c+a\right)+6abc-a^3-b^3-c^3\)

\(=3ab\left(a+b\right)+3bc\left(b+c\right)+3ca\left(c+a\right)+6abc\)

\(=3\left(ab\left(a+b\right)+bc\left(b+c\right)+ca\left(c+a\right)+2abc\right)\)

\(=3\left(ab\left(a+b\right)+b^2c+abc+bc^2+c^2a+ca^2+abc\right)\)

\(=3\left(ab\left(a+b\right)+bc\left(a+b\right)+c^2\left(a+b\right)+ac\left(a+b\right)\right)\)

\(=3\left(a+b\right)\left(ab+bc+c^2+ac\right)\)

\(=3\left(a+b\right)\left[b\left(a+c\right)+c\left(a+c\right)\right]\)

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

29 tháng 8 2017

Tự làm đê em ơi cô Viết cho xong lên mạng chứ j

30 tháng 8 2017

thg kia m nói ai là em hả