1) x² + 2x + 1
= x² + 2.x.1 + 1²
= ( x + 1 )²
2) x² + 10x + 25
= x² + 2.x.5 + 5²
= ( x + 5 )²
3) 4x²+ 20x + 25
= ( 2x )² + 2.2x.5 + 5²
= ( 2x + 5 )²
4) x² - 12x + 36
= x² - 2.x.6 + 6²
= ( x - 6 )²
5) 9 - 12x + 4x²
= 3² - 2.3.2x + (2 x )²
= ( 3 - 2x )²
6) 9x² - 6x + 1
= (3x)² - 2.3x.1 + 1²
= ( 3x - 1 )²
Bài 2 :
1/ x² - 1/4
= x² - ( 1/2 )²
= ( x + 1/2 ) ( x - 1/2 )
2/ 4 - 9x²
= 2² - ( 3x )²
= ( 2 + 3x ) ( 2 - 3x )
3/ 4x² - 1
= ( 2x)² - 1²
= ( 2x + 1 ) ( 2x - 1 )
4/ 4x²y² - 9
= ( 2xy )² - 3²
= ( 2xy + 3 )( 2xy - 3 )
5/ 1/4 x² - 1/9 y²
= ( 1/2 x)² - ( 1/3 y) ²
= ( 1/2 x + 1/3 y ) ( 1/3 x - 1/3 y )
6/ x^4 - y²
= (x² )² - y²
= ( x² - y ) ( x² + y )
7/ 49x² - 36y^4
= ( 7x )² - ( 6y² )²
= ( 7x + 6y²) ( 7x - 6y² )
Xin câu trả lời hay nhất và 5 sao ạ !
