Question 164188
{{{x^2-4x-2=0}}}
{{{(x^2-4x)-2=0}}}
Take 1/2 of the x coefficient and square it.
{{{(-4/2)^2=4}}}
Add that to both sides of the equation.
{{{(x^2-4x+4)-2=4}}}
{{{(x-2)^2=6}}}
{{{(x-2)=0 +- sqrt(6)}}}
{{{x=2 +- sqrt(6)}}}
or approximately,
{{{x=-.45}}}
{{{x=4.45}}}
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Check of the solution by graphing the original function. 
{{{ graph( 300, 300, -2, 6, -5, 5, x^2-4x-2) }}}