Question 311179
<pre><b>
The equation {{{ax^2+bx+c=0}}} has solution

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

For the problem:

{{{x^2-2x+13=0}}}

{{{a=1}}}, {{{b=-2}}}, {{{c=13}}}

{{{x = (-(-2) +- sqrt( (-2)^2-4*(1)*(13) ))/(2*(1)) }}}

{{{x = (2 +- sqrt( 4-52 ))/2 }}}

{{{x = (2 +- sqrt(-48))/2 }}}

{{{x = (2 +- sqrt(-1*48))/2 }}} 

{{{x = (2 +- sqrt(-1)sqrt(48))/2 }}} 

{{{x = (2 +- i*sqrt(16*3))/2 }}}

{{{x = (2 +- i*sqrt(16)sqrt(3))/2 }}}

{{{x = (2 +- i*4sqrt(3))/2 }}}

{{{x = (2 +- 4i*sqrt(3))/2 }}}

{{{x = (2(1 +- 2i*sqrt(3)))/2 }}}

{{{x = (cross(2)(1 +- 2i*sqrt(3)))/cross(2) }}}

{{{x = 1 +- 2i*sqrt(3) }}}

Edwin</pre>