Determine the constant that should be added to the binomial so that it becomes a perfect square trinomial. Then, write and factor the trinomial.

$x^2+16x$

What is the constant that should be added to the binomial so that it becomes a perfect square trinomial?

$64$

Write the trinomial.

$x^2+16x+64($Do not factor.$)$

Factor the result.

$($Simplify your answer.$)$