Alright let me start from the beginning.

So we have

What I do here first is I move the "loose" number over to right.

Now we have

Now I take the coefficient on

and divide it through the entire equation.

Now my method tells me that I take half of the middle term, square it and then add it to both sides.

We end up with this.

This is where I got stuck. I don't know how to get the common denominator of 4a for -c/a. I hope I wrote everything out correctly as I was doing this through memory, and keeping track of exponents and what not can be a little tough when typing it out lol.