For each pair. of expressions below without substituting in specific values ,determine which of the expressions in the given pairs is larger .explain your reasoning in a sentence or two. 5+t^2 and 3-t^2.
15/×^2+6 and 15/x^2 +7.
(s^2+2) (s^2+1) and (s^2+4)(s^2 +3)
8/k^2+2 and k^2+2