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9 tháng 10 2019

a) x+ 3x2 + 4

= [ ( x)2 + 4x2 + 22 ] - x2

= ( x+ 2 )2 - x2

= ( x2 + 2 - x2 ).( x2 + 2 + x)

= 2( 2x2 + 2 )

b) x4 + 5x2 + 9

= [ ( x)2 + 6x2 + 32 ] - x2

= ( x+ 3 )2 - x2

= ( x2 + 3 - x2 )( x2 + 3 + x2 )

= 3( 2x2 + 3 )

21 tháng 8 2021

=8x^2+12x=4x(2x+3)

\(x^2+7x^2+12x=8x^2+12x=4x\left(2x+3\right)\)

29 tháng 8 2018

mk viết đáp án, ko biết biến đổi ib mk

a)  \(x^3+3x^2y-9xy^2+5y^3=\left(x+5y\right)\left(x-y\right)^2\)

b)    \(x^4+x^3+6x^2+5x+5=\left(x^2+5\right)\left(x^2+x+1\right)\)

c)   \(x^4-2x^3-12x^2+12x+36=\left(x^2-6\right)\left(x^2-2x-6\right)\)

d)   \(x^8y^8+x^4y^4+1=\left(x^2y^2-xy+1\right)\left(x^2y^2+xy+1\right)\left(x^4y^4-x^2y^2+1\right)\)

11 tháng 8 2019

\(\text{a) }x^3y^3+x^2y^2+4\)

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

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

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

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

11 tháng 8 2019

\( {c)}\)\(x^4+x^3+6x^2+5x+5\)

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

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

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

\({d)}\)\(x^4-2x^3-12x^2+12x+36\)

\(=\left(x^4-2x^3-6x^2\right)-\left(6x^2-12x-36\right)\)

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

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

Câu b sai đề thì phải ah

19 tháng 10 2020

a) x2 - 4x + 2 = (x2 - 4x + 4) - 2 = (x - 2)2 - 2 = \(\left(x-2+\sqrt{2}\right)\left(x-2-\sqrt{2}\right)\)

b)  x2 - 12x + 11 = x2 - x - 11x + 11 = x(x - 1) - 11(x - 1) = (x - 1)(x - 11)

c) 3x2 + 6x - 9 = 3x2 - 3x + 9x - 9 = 3x(x - 1) + 9(x - 1) = (3x + 9)(x - 1) = 3(x + 3)(x - 1)

d) 2x2 - 6x + 2 = 2(x2 - 3x + 1) = 2(x2 - 3x + 9/4 - 5/4) = 2[(x - 3/2)2 - 5/4] = \(2\left(x-\frac{3}{2}+\sqrt{\frac{5}{4}}\right)\left(x-\frac{3}{2}-\sqrt{\frac{5}{4}}\right)\) 

19 tháng 10 2020

1. 

a) \(x^2-4x+2=\left(x^2-4x+4\right)-2=\left(x-2\right)^2-2=\left(x-2-\sqrt{2}\right)\left(x-2+\sqrt{2}\right)\)

b) \(x^2-12x+11=\left(x^2-12x+36\right)-25=\left(x-6\right)^2-5^2=\left(x-6-5\right)\left(x-6+5\right)=\left(x-11\right)\left(x-1\right)\)

c) \(3x^2+6x-9=3\left(x^2+2x-3\right)=3\left[\left(x^2+2x+1\right)-4\right]=3\left[\left(x+1\right)^2-2^2\right]=3\left(x-1\right)\left(x+3\right)\)

d) \(2x^2-6x+2=2\left(x^2-3x+1\right)=2\left(x^2-2.x.\frac{3}{2}+\frac{9}{4}-\frac{5}{4}\right)=2\left[\left(x-\frac{3}{2}\right)^2-\frac{5}{4}\right]\)

\(=2\left(x-\frac{3}{2}-\frac{\sqrt{5}}{2}\right)\left(x-\frac{3}{2}+\frac{\sqrt{5}}{2}\right)\)

13 tháng 11 2019

1) \(x^2-6x+3\)

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

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

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

2) \(2m^2+10m+8\)

\(=2m^2+2m+8m+8\)

\(=2m\left(m+1\right)+8\left(m+1\right)\)

\(=\left(2m+8\right)\left(m+1\right)\)

\(=2\left(m+4\right)\left(m+1\right)\)

3) \(9x^2+6x-8\)

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

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

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

4) \(x^3-5x^2-14x\)

\(=x\left(x^2-5x-14\right)\)

\(=x\left(x^2-2x+7x-14\right)\)

\(=x\left[x\left(x-2\right)+7\left(x-2\right)\right]\)

\(=x\left(x+7\right)\left(x-2\right)\)

13 tháng 11 2019

1) x^2-6x+3

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

=(x-3)^2-6

=(x-3-căn 6)(x-3+căn 6)

2) =2(m^2+5m+4)

=2(m+1)(m+4)

3) =9x^2+6x+1-9

=(3x+1)^-9

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

4, x^3-5x^2-14x

=x(x-7)(x+2)

5, a^4+4a^2-5

=a^4+4a^2+4-9

=(a^2+2)^-9

=(a^2-1)(a^2+5)

6, x^3-7x-6

=(x-3)(x+1)(x+2).

21 tháng 7 2019

1.a)\(x^2-ax+bx-ab=x\left(x-a\right)+b\left(x-a\right)=\left(x+b\right)\left(x-a\right)\)

b)\(x^2+ay-y^2-ax=\left(x-y\right)\left(x+y\right)-a\left(x-y\right)=\left(x+y-a\right)\left(x-y\right)\)

c)\(x^3-3x^2-4x+12=x^2\left(x-3\right)-4\left(x-3\right)=\left(x^2-4\right)\left(x-3\right)=\left(x-2\right)\left(x+2\right)\left(x-3\right)\)

2.a)\(2x^2-12x=-18=>2x^2-12x+18=0=>x^2-6x+9=0=>\left(x-3\right)^2=0=>x-3=0=>x=3\)b)\(\left(4x^2-4x+1\right)-x^2=0=>3x^2-3x-x+1=3x\left(x-1\right)-\left(x-1\right)=\left(3x-1\right)\left(x-1\right)=0\)

\(=>\orbr{\begin{cases}3x-1=0\\x-1=0\end{cases}=>\orbr{\begin{cases}x=\frac{1}{3}\\x=1\end{cases}}}\)

21 tháng 7 2019

a) 2x2 - 12x = -18

<=> 2x2 - 12x + 18 = 0

<=> 2(x2 - 6x + 9) = 0

<=> 2(x2 - 2.x.3 + 9) = 0

<=> 2(x - 3)2 = 0

<=> x - 3 = 0

<=> x = 0 + 3

<=> x = 3

b) (4x2 - 4x + 1) - x2 = 0

<=> 4x2 - 4x + 1 - x= 0 

<=> 3x2 - 4x + 1 = 0

<=> 3x2 - x - 3x + 1 = 0

<=> x(3x - 1) - (3x - 1) = 0

<=> \(\orbr{\begin{cases}\left(3x-1\right)=0\\\left(x-1\right)=0\end{cases}}\)<=> \(\orbr{\begin{cases}x=\frac{1}{3}\\x=1\end{cases}}\)

=> \(\orbr{\begin{cases}x=\frac{1}{3}\\x=1\end{cases}}\)

30 tháng 7 2015

a. \(=6.\left(x^2+2x+1\right)=6\left(x+1\right)^2\)

b. \(=8x^2-6x+4x-3=2x\left(4x-3\right)+\left(4x-3\right)=\left(2x+1\right)\left(4x-3\right)\)

c. \(=8x^2+6x-4x-3=2x\left(4x+3\right)-\left(4x+3\right)=\left(2x-1\right)\left(4x+3\right)\)