The possible values of 1x2+3 lie in the interval
We know that x2≥0∀x∈R
⇒x2+3≥3;∀x∈R
3≤x2+3<∞
⇒13≥1x2+3>1∞
⇒0<1x2+3≤13
So, the possible values of 1x2+3 lie in the interval (0,13]
The possible values of x2+4 lie in the interval