A perfect square trinomial is of the form
Consider
This satisfies for p = 4 and q = 6. Hence it is a perfect square trinomial.
Consider
This not satisfies as if we compare
but
Hence it is not a perfect square trinomial.
Consider
It can be written as
Let
Then the trinomial becomes
This satisfies for p = 3 and q = 5. Hence it is a perfect square trinomial.
Consider
It is not in the perfect square trinomial form.
Hence it is not a perfect square trinomial.