Hello!
x² + 6x + 1 = 0 <=>
<=> x = -6±√6²-4×1×1/2×1 <=>
<=> x = -6±√36-4/2 <=>
<=> x = -6±√32/2 <=>
<=> x = -6±2²√2/2 <=>
<=> x = -6±4√2/2 <=>
<=> x = -6+4√2/2 <=>
and
<=> x = -6-4√2/2 <=>
<=> x = -3+2√2 <=>
and
<=> x = -3-2√2 <=>
x1 = -3-2√2 and x2 = -3+2√2
Good luck! :)