Question

bài 1: phân tích đa thức thành nhân tử

a) 4²-12xy+9y²

b) x₂-9x+20

c)x²+7x+12

giúp mk vs ạ

Answer 1

\(x^2-9x+20=x^2-5x-4x+20=x\left(x-5\right)-4\left(x-5\right)=\left(x-4\right)\left(x-5\right)\)

\(x^2+7x+12=x^2+3x+4x+12=x\left(x+3\right)+4\left(x+3\right)=\left(x+4\right)\left(x+3\right)\)

Answer 2

b, x² - 9x + 20

= x² - 5x - 4x + 20

= ( x² - 5x ) - ( 4x + 20 )

= x( x - 5 ) - 4( x - 5 )

= ( x - 4 ). ( x - 5 )

c, x² + 7x + 12

= x² + 3x + 4x + 12

= ( x² + 3x ) + ( 4x + 12 )

= x( x + 3 ) + 4( x + 3 )

= ( x + 4 ). ( x + 3 )