Question

factorise x cube + 13 x square + 32 X + 20

Answer 1

Answer:

Let p (x) = x^3 + 13x^2 +32x + 20

Using hit and trial method

x= -1

p (-1) = -1 + 13 -32 +20

=-33+ 33

= 0

So, (x +1 ) is a factor of p (x) [by factor theorem]

To fing other factors we must divide p (x) by (x+1)

And the other factor found is x^2 +12x + 10

Factorising x^2 +12x +20

= x^2 +10x + 2x +20

= x (x +10) +2 (x +10)

= (x+2)(x+10)

So, polynomial p (x) would be factorised as (x+2)(x +10)(x+1).