Question

if using the method of completing the square to solve the quadratic equation below, which number would have to be added to \complete the square\?

$x^{2}-4x = 12$

Explanation:

Step1: Recall the formula

For a quadratic equation of the form $x^{2}+bx = c$, the number to add to complete the square is $(\frac{b}{2})^{2}$.

Step2: Identify the value of b

In the equation $x^{2}-4x = 12$, $b=-4$.

Step3: Calculate the number to add

$(\frac{b}{2})^{2}=(\frac{-4}{2})^{2}=(-2)^{2}=4$.

Answer:

4