Solving quadratic equations by completing the square

Notes:

4-step approach:
1. isolate X’s on one side of the equation
2. factor out the leading coefficient of $X^2$
3. “completing the square”
• X-side: inside the bracket, add (half of the coefficient of $X)^2$
• Y-side: add [ leading coefficient $\cdot$ (half of the coefficient of $X)^2$ ]
4. clean up
• X-side: convert to perfect-square form
• Y-side: clean up the algebra