Question 3417
2x(5x-8)=1
Distribute:  10x^2-16x=1
Subtract 1:  10x^2-16x-1=0
Use quadratic formula: {{{x = (-b +- sqrt( b^2-4*a*c ))/(2*a) }}} 
{{{x = (8 +- sqrt( 8^2-4*10*1 ))/(2*10) }}}
{{{x = (8 +- sqrt( 44 ))/(20) }}}
{{{x = (8 +- 2*sqrt(11 ))/(20) }}}
{{{x = (4 +- sqrt( 11))/(10) }}}