Answer:
[tex](x+9)^2=-4[/tex]Step by step explanation:
Completing the square is where we take a quadratic equation like this:
[tex]\begin{gathered} ax^2+bx+c=0 \\ \text{ and turn it into this:} \\ a(x+d)^2+e=0 \end{gathered}[/tex]Where d and e can be represented by the following expressions:
[tex]\begin{gathered} d=\frac{b}{2a} \\ e=c-\frac{b^2}{4a} \end{gathered}[/tex]Since we have the following equation:
[tex]\begin{gathered} x^2+18x+74=-11 \\ x^2+18x+85=0 \end{gathered}[/tex]So, for a=1, b=18 and c=85.
Find d and e:
[tex]\begin{gathered} d=\frac{18}{2}=9 \\ e=85-\frac{18^2}{4}=4 \end{gathered}[/tex]Then, the result for completing the square would be:
[tex]\begin{gathered} (x+9)^2+4=0 \\ (x+9)^2=-4 \end{gathered}[/tex]