Optimize Your Equation: Solve and Simplify » (𝑥² + likewise for y² + z²) – A Step-by-Step Guide

If you’ve ever come across the equation  (𝑥² + y² + z²) – 2𝑥 – 2𝑧 + 2 = 2, you're not alone. This mathematical expression combines algebraic manipulation and geometric interpretation, making it a great example for learners, students, and anyone exploring quadratic surfaces. Today, we’ll break down how to simplify and interpret this equation — turning it into a clearer, actionable form.


Understanding the Context

Understanding the Equation

The given equation is:

(𝑥² + y² + z²) – 2𝑥 – 2z + 2 = 2

At first glance, it’s a quadratic in three variables, but notice how several terms resemble the expansion of a squared binomial. This realization is key to simplifying and solving it.

Key Insights

Step 1: Simplify Both Sides

Subtract 2 from both sides to simplify:

(𝑥² + y² + z²) – 2𝑥 – 2z + 2 – 2 = 0

Simplify:

𝑥² + y² + z² – 2𝑥 – 2z = 0

Final Thoughts

Step 2: Complete the Square

Group the terms involving 𝑥 and z to complete the square:

  • For 𝑥² – 2𝑥:
    𝑥² – 2𝑥 = (𝑥 – 1)² – 1
  • For z² – 2z:
    z² – 2z = (z – 1)² – 1

Now substitute back:

(𝑥 – 1)² – 1 + y² + (z – 1)² – 1 = 0

Combine constants:

(𝑥 – 1)² + y² + (z – 1)² – 2 = 0

Move constant to the right:

(𝑥 – 1)² + y² + (z – 1)² = 2