x^4+2005x^2+2004x+2005

=x^4-x+2005x^2+2005x+2005

=x(x^3-1)+2005(x^2+x+1)

=x(x-1)(x^2+x+1)+2005(x^2+x+1)

=(x^2+x+1)(x^2-x+2005)

x⁴ + 2005x² + 2004x + 2005 

=x⁴-x+2005x²+2005x+2005

=x(x³-1)+2005.(x²+x+1)

=x(x-1)(x²+x+1)+2005.(x²+x+1)

=(x²+x+1)[x(x-1)+2005]

=(x²+x+1)(x²-x+2005)

       \(x^4+2004x^2+2003x+2004\)

\(=x^4-x+2004x^2+2004x+2004\)

\(=x\left(x^3-1\right)+2004\left(x^2+x+1\right)\)

\(=x\left(x-1\right)\left(x^2+x+1\right)+2004\left(x^2+x+1\right)\)

\(=\left(x^2+x+1\right)\left(x^2-x+2004\right)\)

\(x^4+2004x^2+2003x+2004\)

\(=x^4+2004x^2+2004x-x+2004\)

\(=\left(x^4-x\right)+2004\left(x^2+x+1\right)\)

\(=x\left(x^3-1\right)+2004\left(x^2+x+1\right)\)

\(=x\left(x-1\right)\left(x^2+x+1\right)+2004\left(x^2+x+1\right)\)

\(=\left(x^2+x+1\right)\left(x^2-x+2004\right)\)

\(x^4+2004x^2+2003x+2004\)

\(=x^4+2004x^2+2004x-x+2004\)

\(=\left(x^4-x\right)+2004\left(x^2+x+1\right)\)

\(=x\left(x^3-1\right)+2004\left(x^2+x+1\right)\)

\(=x\left(x-1\right)\left(x^2+x+1\right)+2004\left(x^2+x+1\right)\)

\(=\left(x^2+x+1\right)\left(x^2-x+2004\right)\)

tìm cặp số a,b thoả mãn điều kiện; 3b/a^2-4=1-125a-3b/6a+13=1-125a

x 4  + 2 x 3  +  x 2  =  x 2 ( x 2  + 2x + 1) =  x 2 x + 1 2

x⁴+4 = (x²)²+2² = x⁴ + 2.x².2 + 4 – 4x²

= (x² + 2)² – (2x)² = (x²-2x+2)(x²+2x+2)

Ta có: \(x^4+4\)

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

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

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

x⁴ + x²y² +y⁴                   

= (x²)² +  x²y² + (y²)²          

= (x²)² +  x²y² + (y²)²  + x²y² - x²y²       

= (x²)² +  2 x²y² + (y²)²  - x²y²      

= (x² + y²)²- (xy)²                  

=(x² + y² + xy)(x² + y² - xy)

x4 + 4

= (x2)2 + 22

= x4 + 2.x2.2 + 4 – 4x2

(Thêm bớt 2.x2.2 để có HĐT (1))

= (x2 + 2)2 – (2x)2

(Xuất hiện HĐT (3))

= (x2 + 2 – 2x)(x2 + 2 + 2x)

x4 – 2x2

(Có x2 là nhân tử chung)

= x2(x2 – 2)