Find p(0), p(1) and p(2) for each of the following polynomials :
(i) `p(y)=y^(2)-y+1`
(ii) `p(t)=2+t+2t^(2)-t^(3)`
(iii) `p(x)=x^(3)`
(iv) `p(x)=(x-1)(x+1)`