Question 1055225
You must mean  {{{2x^2-20x+14=0}}}.


{{{x^2-10x+7=0}}}


{{{x=(10+- sqrt(100-4*7))/2}}}


{{{x=(10+- sqrt(72))/2}}}


{{{x=(10+- 6*sqrt(2))/2}}}


{{{x=5+- 3*sqrt(2)}}}