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6 tháng 7 2017

\(x^3+9x^2+26x+24\)

\(=x^3+3x^2+6x^2+18x+8x+24\)

\(=\left(x^3+3x^2\right)+\left(6x^2+18x\right)+\left(8x+24\right)\)

\(=x^2\left(x+3\right)+6x\left(x+3\right)+8\left(x+3\right)\)

\(=\left(x+3\right)\left(x^2+6x+8\right)\)

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

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

\(=\left(x+3\right)\left[x\left(x+2\right)+4\left(x+2\right)\right]\)

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

6 tháng 7 2017

\(15^3+29x^2-8x-12=15x^3+30x^2-x^2-2x-6x-12\)

\(15x^2.\left(x+2\right)-x.\left(x+2\right)-6.\left(x+2\right)\)\(\left(x+2\right).\left(15x^2-x-6\right)\)

\(\left(x+2\right).\left(15x^2-10x+9x-6\right)\)\(\left(x+2\right).\left(3x-2\right).\left(5x+3\right)\)

\(x^3+9x^2+26x+24=x^3+3x^2+6x^2+18x+8x+24\)\(=x.^2\left(x+3\right)+6x.\left(x+3\right)+8.\left(x+3\right)\)\(=\left(x+3\right).\left(x^2+6x+8\right)\)\(\left(x+3\right).\left(x^2+2x+4x+8\right)=\left(x+2\right).\left(x+3\right).\left(x+4\right)\)

6 tháng 7 2017

Ta có : 15x3 + 29x2 - 8x - 12

= 15x3 + 30x2 - x2 - 8x - 12

= 15x(x + 2) - (8x + 16) - (x2 - 4)

= 15x(x + 2) - 8(x + 2) - (x - 2)(x + 2)

= (x + 2)(15x - 8 - x + 2)

= (x + 2) (14x - 6) 

 click zô nha >_<                 

6 tháng 7 2017

Ta có : 15x3 + 29x2 - 8x - 12

= 15x3 + 30x2 - x2 - 8x - 12

= 15x(x + 2) - (8x + 16) - (x2 - 4)

= 15x(x + 2) - 8(x + 2) - (x - 2)(x + 2)

= (x + 2)(15x - 8 - x + 2)

= (x + 2) (14x - 6)

3 tháng 8 2017

(x+2)(14x-6)

29 tháng 11 2016

x3+9x2+26x+24

=(x3+7x2+12x)+(2x2+14x+24)

=x(x2+7x+12)+2(x2+7x+12)

=(x+2)(x2+7x+12)

=(x+2)(x2+4x+3x+12)

=(x+2)[x(x+4)+3(x+4)]

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

15 tháng 10 2021

Bài 2: 

a: \(x^2+5x-6=\left(x+6\right)\left(x-1\right)\)

b: \(5x^2+5xy-x-y\)

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

\(=\left(x+y\right)\left(5x-1\right)\)

c:\(-6x^2+7x-2\)

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

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

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

15 tháng 10 2021

1.

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

b) \(=\left(x+y\right)^3-\left(x+y\right)=\left(x+y\right)\left[\left(x+y\right)^2-1\right]\)

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

c) \(=5\left[\left(x^2-2xy+y^2\right)-4z^2\right]=5\left[\left(x-y\right)^2-4z^2\right]\)

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

2.

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

b) \(=5x\left(x+y\right)-\left(x+y\right)=\left(x+y\right)\left(5x-1\right)\)

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

3.

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

c) \(=-\left[5x\left(x-3\right)-1\left(x-3\right)\right]=-\left(x-3\right)\left(5x-1\right)\)

4.

a) \(\Rightarrow\left(x-1\right)\left(5x-1\right)=0\)

\(\Rightarrow\left[{}\begin{matrix}x=1\\x=\dfrac{1}{5}\end{matrix}\right.\)

b) \(\Rightarrow2\left(x+5\right)-x\left(x+5\right)=0\)

\(\Rightarrow\left(x+5\right)\left(2-x\right)=0\)

\(\Rightarrow\left[{}\begin{matrix}x=-5\\x=2\end{matrix}\right.\)

22 tháng 5 2015

=5x^2-6x-20x+24=x(5x-6)+4(5x-6)=(5x-6)(x-4)

30 tháng 5 2018

45 + x 3 - 5 x 2 - 9 x = x 3 - 5 x 2 - 9 x - 45 = x 2 x - 5 - 9 x - 5 = x - 5 x 2 - 9 = x - 5 x - 3 x + 3

6 tháng 8 2023

\(\text{x^3 – 5x^2 + 8x – 4 }\)

\(\text{= x^3 – 4x^2 + 4x – x^2 + 4x – 4}\)

\(\text{= x( x^2 – 4x + 4 ) – ( x^2 – 4x + 4 )}\)

\(\text{= ( x – 1 ) ( x – 2 )^2}\)

6 tháng 8 2023

\(x^3-5x^2+8x-4=x^3-x^2-4x^2+4x-4\\ =x^2\left(x-1\right)-4x\left(x-1\right)+4\left(x-1\right)\\ =\left(x^2-4x+4\right)\left(x-1\right)\\ =\left(x-2\right)^2\left(x-1\right)\)