Solve $x^2+6x+12=0$ by completing the square.

What constant should you add to the expression $x^2+6x$ to form a perfect square trinomial?

Solve $2x^2+8x+5=0$ by completing the square.

Rewrite $4x^2+24x+25$ in vertex form by completing the square.

A ball's height, in units of feet, is given by: $h\left(t\right)=-16t^2+64t+80$, where $t$ is in units of seconds. Use completing the square to find the time when the ball reaches its maximum height.