a) x=1 => E(1)=[ (1+2)^2 -1-2] /(1+1)
E(1)= [9-3] /2= 6/2= 3
b) (x+2)^2 -x-2= x^2+4x+4-x-2= x^2+3x+2= x^2+x+2x+2= x(x+1) +2(x+1)= (x+1)(x+2)
c) conf punctului a) pt a=1 E(a) este nr natural
daca a= 3 => [(3+2)^2 -3-2]/ (3+1)= (25-5)/4= 20/4= 5
E(a) este nr natural pt oricare ar fi a
