(81x^4+36x^2+4) - 36x^2 = (9x^2+2)^2 - (6x)^2 = (9x^2+2-6x)(9x^2+2+6x)

\(81x^4+4=\left(9x^2\right)^2+36x^2+4-36x^2\)

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

81x⁴ + 4

= 81x⁴ + 36x² + 4 - 36x²

= ( 81x⁴ + 36x² + 4 ) - 36x²

= ( 9x² + 2 )² - ( 6x )²

= ( 9x² - 6x + 2 )( 9x² + 6x + 2 )

81x⁴ + 4

= (9x²)² + 2²

= ( 9x² + 2 )( 9x² - 2 )

81x^4+4

=(9x^2)^2+36x^2+2^2-36x^2

=(9x^2)^2+36x^2+2^2-(6x)^2

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

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

81x⁴ + 4 = ( 9x²)² + 2 ² = ( 9x²)² + 36x² + 2² -  36x² = (9x² + 2)² - (6x)² = (9x² + 2 - 6x)(9x² + 2 + 6x)

XONG

=(84x⁴ + 36x² +4) - 36x²

=(9x² + 2)² - (6x)²

=(9x² + 2 - 6x)(9x² + 2 - 6x)

 64x⁴ + y⁴ = (8x²)² +16x²y²+  (y²) - 16x²y² = (8x²+y²)² - (4xy)² = (8x²+y²- 4xy) (8x²+y² + 4xy)

mk chỉ hơi chửi tục tí thôi nhưng địt con mẹ mình hiền lắm

64⁴+y⁴=(8x²)²+16x²y²+(y²)²-16x²y²=(8x²+y²)²-(4xy)²=(8x²+4xy+y²)(8x²-4xy+y²)

\(64x^4+y^4=64x^4+16x^2y^2-16x^2y^2+y^4\)

\(=\left(64x^4+16x^2y^2+y^4\right)-16x^2y^2\)

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

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

81x²+4 = 4*(\(\frac{81}{4}x^2+1\))

\(81x^4+4\)

\(=81x^4+36x^2+4-36x^2\)

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

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