Question

factorise x³-3x²-9x-5

Answer 1

(x+1)is a factor of x^3-3x^2-9x-5.

so x^3-3x^2-9x-5=x^2-4x-5

x^2-4x-5=(x+1)(x-5)

there fore x^3-3x^2-9x-5=(x+1)^2(x-5)

Answer 2

Given equation is x^3 - 3x^2 - 9x - 5.

x + 1 is the factor. 

x^3 + x^2 - 4x^2 - 4x - 5x - 5 

x^2 (x + 1) - 4x (x + 1) - 5 (x + 1) 

 (x + 1) (x^2 - 4x - 5) 

(x+1)(x² - 5x + x - 5)

= (x + 1) (x - 5) (x + 1). 


Hope this helps!