Question

5. Factorise :
(i) x3 - 2x2 -- x + 2
(iii) x3 + 13x2+32x + 20​

Answer 1

f(x) =x³-2x²-x+ 2

as x=1 is foctor of f(x) by hit and trial method

so (x-1) is factor of f(x) ;and divide f(x) from (x-1) in order to find other factor

x-1) x³-2x²-x+2 ( x²-x-2

_ x³-x²

-------------------

-x²-x

_ -x²+x

-----------------

-2x+2

_ -2x+2

-----------------

0 0

so other factorial is:-

x² - x -2

x² - (2x-x) -2

x(x-2) +1 (x-1)

(x-2) (x+1)

factors are :-

(x-1) (x+1) (x-2)

x = 1; -1 ; 2