Question

Factorise : x3 − 3x2 − 9x − 5.(x cubed-3x sq-5)

Answer 1

p(x)=x³-3x²-9x-5

p(-1)=0

x+1 is a factor of p(x)

x³-3x²-9x-5=(x+1)(x²-4x-5)=(x+1)(x+1)(x-5)

x³-3x²-9x-5=(x+1)²(x-5)