Question

Phân tích đa thức thành nhân tử bằng phương pháp tách hạng tử

a)x²-3x+2

b)2x²-x-6

c)x²-5x-6

d)x²+8x+7

e)3x²+2x-5

f)4x²-3x-1

Answer 1

a) x² - 3x + 2 = x² - x - 2x + 2 = x( x - 1 ) - 2( x - 1 ) = ( x - 1 )( x - 2 )

b) 2x² - x - 6 = 2x² - 4x + 3x - 6 = 2x( x - 2 ) + 3( x - 2 ) = ( x - 2 )( 2x + 3 )

c) x² - 5x - 6 = x² + x - 6x - 6 = x( x + 1 ) - 6( x + 1 ) = ( x + 1 )( x - 6 )

d) x² + 8x + 7 = x² + x + 7x + 7 = x( x + 1 ) + 7( x + 1 ) = ( x + 1 )( x + 7 )

e) 3x² + 2x - 5 = 3x² - 3x + 5x - 5 = 3x( x - 1 ) + 5( x - 1 ) = ( x - 1 )( 3x + 5 )

f) 4x² - 3x - 1 = 4x² - 4x + x - 1 = 4x( x - 1 ) + ( x - 1 ) = ( x - 1 )( 4x + 1 )

Answer 2

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

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

c, \(x^2-5x-6=x^2+x-6x-6=\left(x+1\right)\left(x-6\right)\)

d, \(x^2+8x+7=x^2+x+7x+7=\left(x+1\right)\left(x+7\right)\)

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

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