Question

Phân tích đa thức thành nhân tử

a) x²+2x-8

b)x²+5x+6

Answer 1

a, x^2 + 2x - 8

= x^2 -2x + 4x - 8

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

= (x + 4)(x - 2)

b, x^2 + 5x + 6

= x^2 + 2x + 3x + 6

= x(x + 2) + 3(x + 2)

= (x + 3)(x + 2)

Answer 2

a/ \(x^2+2x-8\)

\(=x^2+4x-2x-8\)

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

\(=x\left(x+4\right)-2\left(x+4\right)\)

\(=\left(x-2\right)\left(x+4\right)\)

b/ \(x^2+5x+6\)

\(=x^2+2x+3x+6\)

\(=\left(x^2+2x\right)+\left(3x+6\right)\)

\(=x\left(x+2\right)+3\left(x+2\right)\)

\(=\left(x+2\right)\left(x+3\right)\)

Answer 3

Trl :

a) x² + 2x - 8

= x² - 2x + 4x - 8

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

= ( x -2 )( x + 4 )

b) x² + 5x + 6

= x² + 2x + 3x + 6

= x( x + 2) + 3( x + 2 )

= ( x + 2)( x + 3 )

Hok tốt :33