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26 tháng 10 2018

      

       \(x^3-27x-54\)

\(=x^3-6x^2+6x^2-36x+9x-54\)

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

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

       \(4x^3-13x^2+9x-18\)

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

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

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

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

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

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

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

8 tháng 10 2016

a ) \(2x^4-9x^3+4x^2+21x-18\)

\(=2x^4-2x^3-7x^3+7x^2-3x^2+3x+18x-18\)

\(=2x^3\left(x-1\right)-7x^2\left(x-1\right)-3x\left(x-1\right)+18\left(x-1\right)\)

\(=\left(2x^3-7x^2-3x+18\right)\left(x-1\right)\)

 

5 tháng 8 2016

\(x^3-4x^2-8x+8\)

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

\(\Leftrightarrow x^2\left(x-4\right)-4\left(x-4\right)\)

\(\Leftrightarrow\left(x-4\right)\left(x^2-4\right)\)

18 tháng 9 2016

\(frac\{3}{4}\)

7 tháng 8 2018

       \(4x^4+4x^3+5x^2+8x-6\)

\(=4x^4-2x^3+6x^3-3x^2+8x^2-4x+12x-6\)

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

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

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

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

       \(4x^4+6x^3-4x^2+9x-15\)

\(=4x^4-4x^3+10x^3-10x^2+6x^2-6x+15x-15\)

\(=4x^3\left(x-1\right)+10x^2\left(x-1\right)+6x\left(x-1\right)+15\left(x-1\right)\)

\(=\left(4x^3+10x^2+6x+15\right)\left(x-1\right)\)

\(=\left[2x^2\left(2x+5\right)+3\left(2x+5\right)\right]\left(x-1\right)\)

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

        

1 tháng 10 2016

\(3x^4+2x^3-8x^2-2x+5\)

\(=3x^4-3x^3+5x^3-5x^2-3x^2+3x-5x+5\)

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

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

\(=\left[3x\left(x^2-1\right)+5\left(x^2-1\right)\right]\left(x-1\right)\)

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

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

b, \(2x^4-9x^3+4x^2+21x-18\)

\(=2x^4-2x^3-7x^3+7x^2-3x^2+3x+18x-18\)

\(=2x^3\left(x-1\right)-7x^2\left(x-1\right)-3x\left(x-1\right)+18\left(x-1\right)\)

\(=\left(2x^3-7x^2-3x+18\right)\left(x-1\right)\)

1 tháng 10 2016

asdf kien