Given a polynomial p(x)=x²-5x+4
(A)Find the value of the polynomial p(x) at x=2
(B)Check whether x is a factor of p(x)
(C)Factorise p(x)

(A) p(x)=x²-5x+4
               x=2  
       p(2)=(2)²-5*2+4  
              =4-10+4
              =-10+8 =-2

(C) p(x)=x²-5x+4
            =x²-4x-x+4
            =x(x-4)-1(x-4)  
            =(x-1)(x-4)