Answer: 
Step-by-step explanation:
A binomial
is called perfect square trinomial
if
is satisfied.
For 
a = 49, b = -28 and c = 16,



Thus,
is not a perfect square trinomial.
For 
a = 4, b = -20 and c = 25,



Thus,
is a perfect square trinomial.
For 
a = 25, b = -20 and c = -16,



Thus,
is not a perfect square trinomial.
For 
a = 16, b = -24 and c = -9,



Thus,
is not a perfect square trinomial.