Factorise :(i) x3−2x2−x+2
x3−2x2−x+2
=x3−x−2x2+2
Grouping the 1st,3rd terms together and the 2nd,4th terms together.
=x(x2−1)−2(x2−1)
=(x2−1)(x−2)
[Using the identity,(a2−b2)=(a−b)(a+b)]
=(x−1)(x+1)(x−2)
Factorise : (i) x3−2x2−x+2 (ii) 2y3+y2−2y−1
Factorise : [4 MARKS] 1)x3−2x2−x+2 2)2y3+y2−2y−1