Question 668998
{{{(1/2)x^2-x+5=0}}}

{{{0.5x^2-x+5=0}}}

{{{x = (-b +- sqrt( b^2-4*a*c ))/(2*a) }}} 

{{{x = (-(-1) +- sqrt( (-1)^2-4*0.5*5 ))/(2*0.5) }}} 

{{{x = (1 +- sqrt( 1-10 ))/1 }}} 

{{{x = (1 +- sqrt( -9 )) }}}... ......we can write {{{-9}}} as {{{(-1)*9}}}

{{{x = (1 +- sqrt((-1)*9))}}} ......we can write {{{sqrt( (-1)*9 )}}} as

{{{sqrt( (-1)*sqrt( 9 ) )}}}


{{{x = (1 +- sqrt( (-1)*sqrt( 9 ) )) }}}...as you know {{{sqrt(-1)=i}}}


{{{x = (1 +- sqrt(9)*i) }}} 

 


so, your answer is: A