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14 tháng 8 2019

\(\frac{\left(6a^3+3a^2+4a+2\right)}{3a^2+2}=\frac{\left(6a^3+4a\right)+\left(3a^2+2\right)}{3a^2+2}=\frac{2a\left(3a^2+2\right)+\left(3a^2+2\right)}{3a^2+2}=\frac{\left(2a+1\right)\left(3a^2+2\right)}{3a^2+2}=2a+1\)

14 tháng 8 2019

\(\frac{a^5+4a^3+3a^2-5a+15}{a^3-a+3}=\frac{\left(a^5-a^3+3a^2\right)+\left(5a^3-5a+15\right)}{a^3-a+3}=\frac{a^2\left(a^3-a+3\right)+5\left(a^3-a+3\right)}{a^3-a+3}=a^2+5\)

30 tháng 5 2018

a) 4x3 - 13x2 + 9x - 18

= 4x3 - 12x2 - x2 + 3x + 6x - 18

= 4x2( x - 3) - x( x - 3) + 6( x - 3)

= ( x - 3)( 4x2 - x + 6)

b) - x3 - 6x2 + 6x + 1

= 6x( 1 - x) + 1 - x3

= 6x( 1 - x) + ( 1 - x )( x2 + x + 1)

= ( 1 - x)( x2 + 7x + 1)

c) x3 + 3x2 + 3x + 2

= x3 + 2x2 + x2 + 2x + x + 2

= x2( x + 2) + x( x + 2) + x + 2

= ( x + 2)( x2 + x + 1)

a) \(4x^3-13x^2+9x-18\)

\(=4x^3-12x^2-x^2+3x+6x-18\)

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

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

15 tháng 9 2018

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

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

\(x^3+6x^2+12x+8=x^3+3.x^2.2+3.x.2^2+2^3=\left(x+2\right)^3\)

\(27x^3-27x^2+9x-1=\left(3x-1\right)^3\)( sửa đề chút )

\(\left(3x+2\right)\left(9x^2-6x+4\right)=\left(3x\right)^3+2^3\)( sửa đề chút )

Tham khảo nhé~

21 tháng 10 2017

b.\(x^3+6x^2+11x+6=0\)

\(\Leftrightarrow x^3+x^2+5x^2+5x+6x+6=0\)

\(\Leftrightarrow x^2\left(x+1\right)+5x\left(x+1\right)+6\left(x+1\right)=0\)

\(\Leftrightarrow\left(x+1\right)\left(x^2+5x+6\right)=0\)

\(\Leftrightarrow\left(x+1\right)\left(x^2+2x+3x+6\right)=0\)

\(\Leftrightarrow\left(x+1\right)\left(x+2\right)\left(x+3\right)=0\)

\(\Leftrightarrow\)\(x+1=0\)hoặc \(x+2=0\)hoặc \(x+3=0\)

\(\Leftrightarrow\)...... tự viết nha bn

21 tháng 10 2017

a)   (6x5 - 3x2):3x - (4x2 + 8x):4x = 5 

\(\Rightarrow\)2x4 - x - x - 2 = 5

\(\Rightarrow\)2(x4 - x -1) = 5

\(\Rightarrow\)x- 2x2  + 1 + 2x2 - 2 = 2.5

\(\Rightarrow\)(x2 - 1)2 + 2(x2 - 1)  + 1 - \(\frac{7}{2}\) = 0

\(\Rightarrow\)x4 = \(\frac{7}{2}\)

\(\Rightarrow\)x  = \(\pm\)\(\sqrt[4]{\frac{7}{2}}\) 

b)   x3 + 6x2 + 11x +6 = 0

\(\Rightarrow\)x3 + 6x2 + 12x + 8 - x - 2 = 0

\(\Rightarrow\)(x + 2)3 - (x + 2) = 0

\(\Rightarrow\)(x + 2)(x-1)(x+3)=0

\(\Rightarrow\)x + 2 = 0    \(\Rightarrow\)x = -2 

         x - 1 =0        \(\Rightarrow\)x = 1

         x + 3 = 0       \(\Rightarrow\)x = -3

Vay.....

14 tháng 8 2019

6x^3+3x^2+4x+2 3x^2+2 2x+1 6x^3 +4x - 3x^2+2 3x^2+2 - 0

14 tháng 8 2019

x^5+4x^3+3x^2-5x+15 x^3-x+3 x^2 x^5-x^3+3x^2 - 5x^3-5x+15 +5 5x^3-5x+15 - 0

11 tháng 7 2021

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

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

\(\left(-x^2+3\right).x^2+3\left(-x^2+3\right)\)

\(-x^2.x^2+3x^2+3\left(-x^2+3\right)\)

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

\(-x^2.x^2+9\)

11 tháng 7 2021

\(\left(2x+5\right)\left(2x-5\right)\)

\(2x\left(2x-5\right)+5\left(2x-5\right)\)

\(4x^2-10x+5\left(2x-5\right)\)

\(4x^2-10x+10x-25\)

\(4x^2-25\)

4 tháng 8 2017

=x4-4x3-2x2+12x+9

=x4+x3-5x3-5x2+3x2+3x+9x+9

=x3(x+1)-5x2(x+1)+3x(x+1)+9(x+1)

=(x+1)(x3-5x2+3x+9)

=(x+1)(x3+x2-6x2-6x+9x+9)

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

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

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

25 tháng 7 2018

\(a.\left(2x-3\right)\left(4x^2+6x+9\right)-\left(2x+3\right)\left(4x^2-6x+9\right)\\ =\left(2x\right)^3-3^3-\left[\left(2x\right)^3+3^3\right]\\ =8x^3-9-\left(8x^3+9\right)\\ =8x^3-9-8x^3-9=-18\)

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

\(c.\left(3x-1\right)\left(3x+1\right)-\left(3x-2\right)^2\\ =9x^2-1-\left(9x^2-12x+4\right)\\ =9x^2-1-9x^2+12x-4\\ =12x-5\)

\(d.\left(2x-3\right)^2-\left(2x+3\right)\left(2x-3\right)\\ =\left(2x-3\right)\cdot\left[\left(2x-3\right)-\left(2x+3\right)\right]\\ =\left(2x-3\right)\cdot\left(2x-3-2x-3\right)\\ =\left(2x-3\right)\cdot\left(-6\right)\\ =-12x\cdot18\)

\(e.\left(3x-4\right)^2-\left(2x+4\right)^2\\ =9x^2-24x+16-\left(4x^2+16x+16\right)\\ =9x^2-24x+16-4x^2-16x-16\\ =5x^2-40x\)

\(f.\left(3x-5\right)^3-\left(3x+5\right)^3\\ =27x^3-135x^2+225x-125-\left(27x^3+135x^2+225x+125\right)\\ =27x^3-135x^2+225x-125-27x^3-135x^2-225x-125\\ =-270x^2-250\)

\(g.\left(2x-1\right)^2-\left(3x-1\right)^2\\ =4x^2-4x+1-\left(9x^2-6x+1\right)\\ =4x^2-4x+1-9x^2+6x-1\\ =-5x^2+2x\)

\(h.\left(x-2y\right)\left(x^2+2xy+4y^2\right)+\left(x^3-6y^3\right)\\ =x^3-8y^3+x^3-6y^3\\ =2x^3-14y^3\)