Question 341595
{{{x^2+20x=6}}} 
To complete the square, take {{{1/2}}} of the x-coefficient({{{b}}}), square it, and add it to both sides.
{{{(1/2)(20)=10}}}
{{{10^2=100}}}
{{{x^2+20x+100=6+100}}}
{{{(x+10)^2=106}}}
{{{x+10=0 +- sqrt(106)}}}
{{{highlight(x=-10 +- sqrt(106))}}}