Verified Answer :

  • Isolate the constant: move \(-3\) to the other side to get \(x^2 + 8x = 3\).
  • Find the constant to add: take half of the coefficient of \(x\) (which is \(8/2 = 4\)) and square it (\(4^2 = 16\)).
  • Add \(16\) to both sides: \(x^2 + 8x + 16 = 3 + 16\).
  • Simplify to the final form: \((x + 4)^2 = 19\).
  • The final result is \((x + \boxed{4})^2 = \boxed{19}\).

Explanation

  1. Analyzing the Quadratic Equation

The objective is to rewrite the quadratic equation \(x^2 + 8x - 3 = 0\) by completing the square to express it in the form \((x + k)^2 = m\). This process involves manipulating the original expression so that the terms involving \(x\) form a perfect square trinomial. We are given the original equation:
\[x^2 + 8x - 3 = 0\]
To start, we isolate the terms containing \(x\) on one side:
\[x^2 + 8x = 3\]

  1. Finding the Constant to Complete the Square

A perfect square trinomial follows the form \((x + k)^2 = x^2 + 2kx + k^2\). Comparing this to our expression \(x^2 + 8x\), we equate the coefficients of \(x\):
\[2k = 8\]
Solving for \(k\), we find:
\[k = \frac{8}{2} = 4\]
To complete the square, we need to add \(k^2\) to both sides of the equation. Calculating \(k^2\):
\[k^2 = 4^2 = 16\]

  1. Completing the Square and Finalizing the Result

Now, we add \(16\) to both sides of the equation \(x^2 + 8x = 3\):
\[x^2 + 8x + 16 = 3 + 16\]
The left side is now a perfect square, \((x + 4)^2\). Simplifying the right side gives \(3 + 16 = 19\). Thus, the equation becomes:
\[(x + 4)^2 = 19\]
Comparing this to the required format \((x + \boxed{\phantom{0}})^2 = \boxed{\phantom{0}}\), we see that the first box is \(4\) and the second box is \(19\).

Examples

Completing the square is a powerful algebraic technique used to solve quadratic equations, find the vertex of a parabola, or simplify complex expressions. In real life, this is useful when modeling physical systems—for instance, calculating the trajectory of a projectile. If you were designing a fountain, you could use this method to determine the highest point the water arc reaches by identifying the vertex of its parabolic path, ensuring your design is both precise and aesthetically pleasing.