Răspuns:
Explicație pas cu pas:
Notam x^2 +2x = p
a) p(p+5) +6 = (p+2)(p+3)
p^2 +5p + 6 = p^2 +3p +2p +6 = p^2 +5p +6
b) E = ((p+2)^2 -1)/(p+2)(p+3) =
(p+2 -1)(p+2 +1)/(p+2)(p+3) =
(p+1)(p+3)/(p+2)(p+3) = (p+1)/p+2)
E(x) = ((x^2 +2x +1)/((x^2+2x +2) =
((x+1)^2/((x+1)^2 +1)
E(x) = minnim cand (x+1)^2 = 0,
deci min(E(x)) = 0/1 = 0
