Answer:
Option A.
Step-by-step explanation:
The given equation is
[tex]x^2+6x=18[/tex]
We need to find the roots using completing the square.
[tex]\left(\dfrac{b}{2}\right)^2=\left(\dfrac{6}{2}\right)^2=3^2=9[/tex]
Add 9 on both sides in the given equation to make it perfect square.
[tex]x^2+6x+9=18+9[/tex]
[tex]x^2+2(x)(3)+3^2=27[/tex]
[tex](x+3)^2=27[/tex]
Taking square root on both sides.
[tex]x+3=\sqrt{27}[/tex]
Subtract 3 from both sides.
[tex]x=-3+\sqrt{27}[/tex]
Therefore, the correct option is A.
