Question

find the solutions for the quadratic equation by completing the square.$x ^{2} + 18x = 63$

Answer 1

Completing the square

$x^2+18x=63$$\begin{gathered} x^2+18x+(\frac{18}{2})^2=63+(\frac{18}{2})^2 \\ x^2+18x+81=63+81 \\ x^2+18x+81=144 \\ (x+9)^2=144 \\ \end{gathered}$$\begin{gathered} (x+9)=\sqrt[]{144} \\ x+9=\pm12 \\ x_1=-12-9 \\ x_1=-21 \\ \\ x_2=12-9 \\ x_2=3 \end{gathered}$

The answer would be -21, 3