Question

phân tích đa thức sau thành nhân từ:

` x^3 - 5x + 4 `

Answer 1

\(x^3-5x+4\)

\(=x^3-x-4x+4\)

\(=x\left(x-1\right)\left(x+1\right)-4\left(x-1\right)\)

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

Answer 2

` x^3 - 5x + 4 `

` = x^3 - x - 4x + 4 `

` = x ( x^2 - 1) - 4 ( x-1) `

` = x ( x-1) ( x+1) - 4 ( x -1 ) `

` = ( x -1) [ x(x+1) - 4] `

` = ( x -1 ) ( x^2 + x - 4 ) `