All possible values of expression x2−4x+9 is
[5,∞)
x2−4x+9= x2−2(2)x+4−4+9
=(x−2)2+5
We know that (x−2)2≥0
(x−2)2+5≥5
(or)
∞ > (x−2)2+5≥5
⇒ (x−2)2+5∈[5,∞)